State of Israel ץיק דעומ Ministry of Education

State of IsraelMinistry of EducationExam Type: BagrutExam date: Summer 2021Exam number: 043381English translation (3)

Note: There are special instructions in this exam. Please answer the questions according to these instructions.

BiologyQuestions and Analysis of

Scientif ic Research in the Core Topic Areas Quest ions on Topics of In-Depth Study

Instructions for examinees

Duration of the exam: Three hours .א :Exam structure and breakdown of points .ב This exam has four parts.

Part One — 32 points Part Two — 35 points

Part Three — 18 points Part Four — 15 points Total — 100 points

:Material that may be used during the exam .ג A Hebrew-foreign language/foreign language-Hebrew

dictionary

:Special instructions .ד Mark your answers to Part One on the answer sheet

provided at the end of the answer booklet (page 19). Answer the questions in Part Two, Part Three and Part Four in the answer booklet.

Write in the answer booklet only. Write the word "טיוטה" at the top of each of draft page.If you write any draft material on paper outside the an-swer booklet, your exam may be disqualified.

G o o d L u c k !

מדינת ישראלמשרד החינוך

סוג הבחינה: בגרותמועד הבחינה: קיץ תשפ"א, 2021

מספר השאלון: 043381תרגום לאנגלית )3(

שים לב: בבחינה זו יש הנחיות מיוחדות. יש לענות על השאלות על פי הנחיות אלה.

ה י ג ו ל ו י ב

עי ד מ ר ק ח מ ח ו ת י נ ו ת ו ל א שה ב י ל ה י א ש ו נ ב

ה ק מ ע ה ה י א ש ו נ ב ת ו ל א ש

הוראות לנבחן

משך הבחינה: שלוש שעות. א.

ב. מבנה השאלון ומפתח ההערכה: בשאלון זה ארבעה פרקים.

32 נקודות – פרק ראשון 35 נקודות – פרק שני 18 נקודות – פרק שלישי

15 נקודות – פרק רביעי 100 נקודות – סה"כ

חומר עזר מותר בשימוש: ג. מילון עברי-לועזי / לועזי-עברי.

הוראות מיוחדות: ד. את תשובותיך על השאלות בפרק הראשון סמן בתשובון

שבסוף מחברת הבחינה )עמוד 19(. את תשובותיך על השאלות בפרק השני, בפרק השלישי

ובפרק הרביעי כתוב במחברת הבחינה.

כתוב במחברת הבחינה בלבד. רשוםֹ "טיוטה" בראש כל עמוד טיוטה. כתיבת טיוטה בדפים שאינם במחברת הבחינה עלול לגרום

לפסילת הבחינה.

! ה ח ל צ ה ב

מועד קיץ

- 2 -Biology, Summer 2021, No. 043381ביולוגיה, קיץ תשפ"א, מס' 043381, אנגלית

QuestionsPart One (32 points)

There are 20 questions, 1-20, in this part. You must answer all of the questions. If you answer at least 15 questions correctly, you will receive all 32 points.

Four possible answers are presented for each question. Choose the most appropriate answer. * Mark the answer you have chosen on the answer sheet at the end of the answer

booklet (page 19). * For each question, draw an × in pen in the box under the letter (א-ד) that represents the

answer you chose.

* Draw only one × for each question. * To erase an answer, fill in the entire box like this: . * You may not use White-Out to erase answers.

/continued on page 3/

Example:

47. Which disease is carried by mosquitoes?

jaundice .א

rubella .ב

malaria .ג

whooping cough .ד

In this case, you would mark your answer on the answer sheet as follows:בא 47.

ג

ד


Note: In order to limit the need to erase answers on the answer sheet, we recommend that you first mark the correct answers inside this booklet and only later enter them into the answer sheet.

Answer all of the questions 1 to 20.

1. Which one of following pairs is a correct match of a blood component and its function?

red blood cells—transporting hormones .א

plasma—producing ATP .ב

white blood cells—transporting CO2 .גplatelets—blood clotting .ד

2. Which statement is true for all living cells?

.They all have a nucleus surrounded by a membrane .א

.They all have 46 chromosomes .ב

.In all of them, the genetic information is located in proteins .ג

.They all use chemical energy .ד

3. A plant called red-berry mistletoe [דבקון הזית] grows on olive trees. The leaves of the mistletoe are

green, and its stems grow shoots that penetrate the olive tree branches and absorb its water and

minerals. Is mistletoe a producer [יצרן]?

.No, because it consumes water and minerals from the olive tree .א

.No, because it lives on olive trees .ב

.Yes, because it makes organic substances from inorganic substances .ג

.Yes, because it absorbs inorganic substances from the environment .ד

4. In a unicellular organism that inhabits vernal pools [שלולית], the enzyme that catalyzes the synthesis

of an energy storage molecule [חומר תשמורת] from monosaccharides [חד־סוכרים] stopped working

properly. What might happen as a result of this?

.The organism will explode .א

.The organism will shrink .ב

.The organism will use more water to produce energy .ג

.The organism will move more slowly through its environment .ד



5. What results from contraction of the right ventricle of the heart?

.[אבי העורקים] Blood flows from the right ventricle to the aorta .א

.Blood flows from the right ventricle to the right atrium .ב

.[עורק הריאה] Blood flows from the right ventricle to the pulmonary artery .ג

.Blood flows from the body veins to the left atrium .ד

6. What is the difference between viruses and bacteria?

.whereas bacteria have a fast metabolic rate ,[קצב חילוף החומרים] Viruses have a slow metabolic rate .א

.Viruses contain either DNA or RNA but not both, whereas bacteria contain both .ב

.Bacteria only reproduce inside cells, whereas viruses reproduce outside cells .ג

.Viruses cause an immune reaction, whereas bacteria do not cause an immune reaction .ד

7. Scientists added either phosphorus (P) compounds or nitrogen (N) compounds to the soil in a certain

habitat to test the compounds' effect on grass growth. Grass growth increased only where they had

added phosphorus compounds.

Which substance was the limiting factor in this habitat, and why?

.Nitrogen, because adding it did not increase grass growth .א

.Phosphorus, because adding it increased grass growth .ב

.Both, because they are both essential to building cell components .ג

.Neither, because grass grew in both cases .ד

8. How is a nerve impulse [אות עצבי] transmitted through the nervous system?

.[תא עצב] A neurotransmitter passes from one synapse to the next through a neuron . א

.An electrical signal passes along the neuron and is transmitted directly to the next neuron .ב

An electrical signal passes through the synapse following the secretion of neurotransmitter by the .ג

neuron.

An electrical signal passes through the neuron and induces secretion of neurotransmitter into the .ד

synapse.

9. Consider this sequence of bases on a single strand of DNA: GTTAGC.

What is the sequence of bases on the complementary strand that is formed after the DNA is replicated?

GTTAGC .א

CAATCG .ב

CAAUCG .ג

GCCTGC .ד



10. A sauna is a very hot room. What happens to the level of the hormone ADH in the blood of a person

who stays in a sauna for a long time without drinking?

.It goes up .א

.It goes down .ב

.It does not change .ג

.It alternately goes up and down .ד

11. In what habitat does a short life cycle give annual plants an advantage?

in a habitat where temperature differences between seasons are not great .א

in a habitat that has high temperatures and rain all year round .ב

in a habitat that is dry for most months of the year .ג

in a habitat where there is no seed dispersal .ד

12. Which statement about compartmentalization [מִידוּר] (the existence of different organelles in a cell)

is correct?

.It is characteristic of prokaryotic cells and not of eukaryotic cells .א

.It only allows processes to take place in the small cells of an organism .ב

.It is characteristic of plant cells but not animal cells .ג

.It allows processes that require different conditions to take place at the same time .ד

13. Consider the four statements below. Which statement is correct for an organism whose body

maintains homeostasis?

.The internal environment of this organism is not the same as its external environment .א

.All the cells in this organism consume the same amount of ATP .ב

.The internal processes in this organism are not affected by its external environment .ג

.All processes taking place in all of this organism's cells are identical .ד

14. Researchers tested a skin cell and a neuron that were taken from a certain person. In what was there

a difference between the two cells?

in their DNA molecules .א

in the number of types of amino acids they contained .ב

in their messenger RNA (mRNA) molecules .ג

in their type of ribosomes .ד



15. Students collected leaves that had fallen to the ground and put them in cloth bags. The fabric of

these bags allows the passage of micro-organisms through it.

The bags were buried in the ground and were weighed several times during the year. The results are

shown in the following graph.

Weight of the leaves over time

Time(months)

Weight of leaves(grams)

What is the explanation for these results?

.Microorganisms decomposed the organic matter in the leaves .א

.The organic matter decomposed during photosynthesis that took place in the leaves .ב

.Microorganisms converted the inorganic substances in the leaves to organic matter .ג

.The leaves shrank in the cold so that they would lose less heat to the environment .ד

16. The gas CO (carbon monoxide) found in cigarette smoke enters the lungs when the cigarette smoke

is inhaled. What happens when CO is inhaled?

.Oxygen binds less strongly to hemoglobin .א

.get clogged and destroyed [סימפונות] The bronchi .ב

.More oxygen reaches the cells .ג

.The amount of CO2 (carbon dioxide) in the blood rises .ד

17. The chance of a mutation that will have a negative effect on the ability of bees to digest sucrose is

very low.

If bees are moved to an environment in which sucrose is their main source of food, how will the

chance of this mutation occurring change?

.The chance will increase greatly .א

.The chance will increase slightly .ב

.The chance will decrease .ג

.The chance will not change .ד /continued on page 7/


18. The following statements relate both to hormones and to neurotransmitters. Which statement is

incorrect?

.They can cause changes in cell activity .א

.They are secreted into the blood .ב

.They can cause changes in animal behavior .ג

.They bind to receptors .ד

19. In which one of the following options א-ד are the items arranged in increasing order of size?

nucleotide, codon, chromosome, gene .א

codon, nucleotide, chromosome, gene .ב

codon, nucleotide, gene, chromosome .ג

nucleotide, codon, gene, chromosome .ד

20. The indicator neutral red is red in an acidic solution and yellow in an alkaline (basic) solution.

Researchers added this indicator to a flask containing yeast cells in an alkaline solution.

The solution turned yellow, and the contents of the yeast cells turned red.

What can we conclude from these results?

.When the base penetrates the yeast cells they die .א

.Yeast cells are able to maintain a pH that is different from their environment .ב

.Yeast cells have a small surface area, so the base cannot penetrate them .ג

.The selective cell membrane does not allow the indicator to penetrate the yeast cells .ד

(Note: Mark your answers on the answer sheet on page 19 at the end of the answer booklet.)




Part Two (35 points)There are seven questions, 21-27, in this part. Choose four questions and write your answers in the answer booklet (each question — 8.75 points).

The following table describes two states that affect the concentration of glucose and of (1) .א .21the hormones insulin and glucagon in the blood of a healthy person. Copy the table to your answer booklet and indicate the effect of each state on the concentration of each substance (choose from the options in parentheses).

Effect of different states on the concentration of substances in the bloodState Glucose concentration

(increase/decrease/no change)

Concentration of the hormone insulin

(increase/decrease/no change)

Concentration of the hormone glucagon (increase/decrease/

no change)Shifting from rest to physical activityEating starch-rich food

(2) List one way in which the hormone insulin reduces the concentration of glucose in the blood of a healthy person.

(5.75 points) are present in body organs. Various substances pass in and out of the [נימי דם] Capillaries .ב

capillaries. The illustration below describes the passage of substances in and out of a capillary in a specific organ.

OxygenGlucose

InsulinCO2

In which organ of the human body is this capillary found? Explain your answer. (3 points)

In the population of a certain species of rodent some individuals have a long tail and the others .א .22have a short tail.

The long tail slows down the rodents and makes it harder for them to escape cats that are preying on them.

How does tail length affect the fitness [כשירות] of the rodents in this population? Explain. (4 points)

A part of the habitat of this population of rodents was enclosed in a fence which prevented the .בrodents from crossing from one side to the other.

Many years after the fence had been built the two populations of rodents—inside and outside the fenced area—were tested. The two populations were found to belong to two separate species.

Explain how two separate species developed from one original population, one on each side of the fence. (4.75 points)

Copy to notebook


.Consider the following two lists .א .23 I Organelles in a plant cell: chloroplasts, mitochondria, nucleus. II Components of the plant cell membrane: channels, carriers, pumps, phospholipids. Choose two organelles from List I. For each organelle you chose, note a substance that is

synthesized in it. Explain how each of the substances you noted affects the structure or activity of a component

in List II. (5.75 points) A mutation in a certain plant caused production of a larger amount of chlorophyll in the .ב

chloroplasts. How can this mutation affect the plant's growth rate? Explain your answer. (3 points)

24. When COVID-19 (Corona) viruses reach the lungs, they penetrate the cells and start to reproduce. As a result fluid accumulates in the alveoli [נאדיות].

Explain why a person will have difficulty using their muscles when fluid accumulates in the .א alveoli. (4 points)

One treatment for infection with COVID-19 that was tested was to extract certain components .בfrom the plasma [נוזל הדם] of a person who had the disease and recovered, and inject them into patients who have the virus.

(1) Is the process that took place in the body of a person who had the disease and recovered active or passive vaccination? Explain.

(2) Is injecting sick people with these components active or passive vaccination? Explain. (4.75 points)

Scientists tested the rate of evaporation of water from the body of the following four mammals .א .25in a warm environment: jerboa, rabbit, man, and donkey [ירבוע, ארנבת, אדם וחמור]. The table below shows the body weight of each of the mammals and the rate of water evaporation relative to body weight.

Mammal Body weight (kg)

Rate of water evaporation

(% of body weight per hour)

Jerboa 0.1 14Rabbit 2.5 5Man 70.0 3Donkey 95.0 2

Based on the table, list the association between the mammals' body weight and the rate of water evaporation from their body. Explain the cause of this association. (4.75 points)

Mammals who live in cold environments have adaptations that help them maintain a more or .בless constant body temperature.

List two adaptations that are not behavioral adaptations, and briefly describe how each one helps animals maintain body temperature in a cold environment. (4 points)



With all other conditions being identical, yeast consume more glucose when oxygen is low .א .26than when oxygen is available. Explain why yeast consume more glucose when oxygen is low. (3.5 points)

Researchers wanted to test the effect of heating yeast cells on the pH and amount of ATP inside .בthe cells. The researchers placed yeast in a solution with pH 4.0. They divided the solution between two containers and heated one of them for 10 minutes at C60o .

The results of this experiment are shown in the following table.

Treatment pH of the solution

Heated at 60 Co

pH inside the cells Amount of ATP in the cells

(relative units)

1 4.0 no 6.2 6.9

2 4.0 yes 4.7 0.065

Explain the effect of heating on cell pH level and on the amount of ATP in the cells. (5.25 points)

27. The table below shows a number of substances that may be found in blood, filtrate from nephrones, and urine.

Body fluid

Substance

Blood Filtrate Urine

Water (yes/no)

Glucose (yes/no)

Urea (yes/no)

Protein (yes/no)

Copy the table to your notebook, and fill in the information for a healthy person using the .אoptions in parentheses. (4.75 points)

.After the filtrate is formed, some of the substances in it are reabsorbed into the blood .ב Choose two of the substances in the table that are reabsorbed, and note for each substance

whether reabsorption is achieved by active transport or by passive transport. (4 points)


Copy to notebook


Part Three (18 points)There are three questions, 28-30, in this part.Read the description of a research study below, and answer all of the questions 28-30. The number of points is given at the end of each item.

The effects of forestation on climate in semi-arid regions*It's hot. We all feel very hot and it is not just a subjective feeling; there is scientific evidence for it.Since 1996, Professor Dan Yakir of the Weizmann Institute of Science and his team have been running experiments in the Yatir Forest, which is a pine forest bordering the desert near Beer Sheva. This region is semi-arid, in other words, it receives little rainfall over a short wet season, and the temperatures there are high. Based on the results of studies in the Yatir Forest, researchers claim that in the long term, planting forests in semi-arid areas can reduce environmental warming.We know that forest trees both affect and are affected by the environment.Read the following text about passage of water and gases between a plant and its environment.

Open stoma(magnified)

Water

Gases enter and exit plants and water exits plants mainly through the stomata pores .[פתחי הפיוניות]When a plant has sufficient water, the stomata in its leaves open, and when a plant experiences water shortage the stomata pores get smaller.

*The information in this part is adapted from the following three sources:

— Yosef, G. et al. [2018]. Large-scale semi-arid afforestation can enhance precipitation and carbon sequestration potential.

Nature, article number 996. 17 January 2018.

— Rotenberg, E. and Yakir, D., Forestation, climate, and the future of forests in Israel. Ecology and Environment. October

2018, 3(22-33). [Hebrew]

— Lecture by Prof. Yakir at the 47th Annual Conference of Science and the Environment. Twenty years in the Yatir Forest:

Local Research—Global Significance. Tel Aviv University channel, YouTube.



.Water evaporation helps to reduce ambient temperature .א .28

Explain how longer roots on trees can help reduce the temperature of the air around the trees.

(2 points)

Scientists at the research station in Yatir Forest have been continuously measuring many factors in

the air, soil, and vegetation in the forest and its surroundings since 1996. One of these factors is the

concentration of CO2 in the air.

The graph below describes the monthly average concentrations of CO2 in the air measured .ב

over 24-hour periods at the end of the summer and the end of the winter.

CO2 concentration in the air in the Yatir Forest over 24 hours in two seasons

Average concentration of CO2 in the air(arbitrary units)

Time00:00 06:00 12:00 18:00 24:00

End of summerEnd of winter

Legend:

When was the concentration of CO2 in the air at 12:00 lower, at the end of the winter or at the end

of the summer? Explain why.

In your explanation, use the information in the box on page 11. (5 points)




In recent years there has been a noticeable upward trend in the concentration of CO2 in Earth's atmosphere. At the same time there has been an increase in air temperature. The researchers compared their findings from the pine forest research station at Yatir with findings from a pine forest in Europe.The climate in the pine forest where the European research station is located is temperate [ממוזג], in other words a climate with a large amount of rainfall spread across the year and low temperatures.The data in the following table shows the amounts of CO2 absorbed and emitted by each of the two forests in one year.

Amounts of CO2 absorbed and emitted by the two forests

Location

Amount of CO2 (gram/m2 forest/year)

Absorbed Emitted Difference between amounts

absorbed and emitted

European forest (temperate climate)

1,144 944 200

Yatir Forest (semi-arid climate)

820 600 220

Determine in which forest—the one in Europe or the one in Yatir—there is a higher level of .א .29photosynthesis and in which forest there is a higher level of cellular respiration [נשימה תאית]. Explain your answer regarding cellular respiration, based on the data in the table. (4 points)

Based on the table, we may hypothesize that the contribution of the Yatir Forest to reducing the .בwarming of its ambient air is greater compared with the European forest. Explain how the data in the table support this hypothesis. (3 points)

The researchers wanted to evaluate whether planting a pine forest much larger than the Yatir Forest would have a similar environmental effect as that of the Yatir Forest. They selected a different region with the same semi-arid climate as Yatir Forest, but with an area 100,000 times larger than Yatir Forest. They then calculated the expected environmental effects in the selected region based on the abundant data collected at the Yatir Forest research station.

30. Based on the studies described in the passage, do you think that it is a good idea to plant a much larger pine forest than Yatir in the selected region? Provide one argument in favor of your opinion and one argument against it. At least one of your arguments must be based on biological considerations. (4 points)In 2019, Professor Yakir received the Israel Prize for his research in Yatir Forest and other studies.


Part Four (15 points)There are three topics in this part:Topic I: Regulation of Gene Expression and Genetic Engineering pages 15-17Topic II: Developmental Comparative Physiology pages 18-19Topic III: Bacteria and Viruses in the Human Body pages 20-21 Choose one topic and answer two questions on that topic, according to the directions given for the topic you chose.

(Note: The exam continues on the next page.)



Topic I — Regulation of Gene Expression and Genetic EngineeringAnswer two questions: Question 31 (required) and one of the questions 32-33. The number of points is given at the end of each item.Answer Question 31 (required).

The PCR method makes it possible to test the genetic material in samples collected from .א .31

people who have illnesses caused by viruses.

Explain the purpose of using the PCR method to do this test. (2 points) The PCR method uses a certain enzyme. The effect of temperature on the activity of such an .ב

enzyme produced from two different sources, A and B, was tested and the results are shown in the following graph.

Effect of temperature on activity of enzymes from different sources

00 20 6040 80

Rate of enzyme activity(arbitrary units) Legend:

Enzyme from Source AEnzyme from Source B

Temperature(oC)

Based on what you know about the PCR method, determine which enzyme is better for using in

this method, the enzyme from Source A or the enzyme from Source B. Explain your answer.

(3 points)

(Note: This question continues on the following page.)



.A certain disease is caused by the different strains of a virus whose genetic material is DNA .גTwo patients were tested to see which strain of the virus each one had caught.

Abloodsample—containingviruses—wascollectedfromeachofthepatients.Inthefirststep of the test the lab applied the PCR method and in the second step the lab used gel electrophoresis.

Before running the gel electrophoresis, a certain restriction enzyme (segmentation enzyme) was applied to the viral DNA.

Thefigurebelowshowsthebindingsitesofthisrestrictionenzymeinthreevirusstrains,K,L,and M.

Strain K

Strain L

Legend:Restriction enzyme binding site

DNA

Strain M

Thefollowingfigureshowstheresultsofgelelectrophoresisofthesamplesfromthetwopatientsafter the samples were digested with the same restriction enzyme.

Sample from

Patient אSample

from Patient ב

Based on these results, determine which strain of the virus eachpatientcaught—K,L,orM.

Explain both answers. (4 points)



Answer one of the questions 32-33.

Micro RNA is a small molecule of RNA that binds to messenger RNA (mRNA) and affects the .א .32

control of protein synthesis in cells.

Micro RNA was added to a cell, and it bound to the RNA of a certain gene. As a result, the

amount of protein that this gene encodes decreased. Suggest an explanation for this.

(2 points)

When a cell's environment changes, it is important to produce certain proteins in the cell (1) .ב

quickly.

Explain why translational regulation [בקרה בשלב התרגום] allows the cell to respond faster

than transcriptional regulation [בקרה בשלב התעתוק].

(2) Determine which of the following components does not play a role in translation:

messenger RNA (mRNA), a nucleotide that contains thymine (T), transfer RNA (tRNA),

ribosomes.

Explain.

(4 points)

33. There are a number of ways to genetically diagnose hereditary diseases.

One method is to examine the karyotype [picture of the chromosomes] of cells from a human .א

fetus.

(1) List one finding that can be discovered using this method.

(2) Explain why a karyotype can show normal results even if the cells of the tested fetus have

a hereditary defect.

(3 points)

Nucleotide sequencing is another type of genetic testing. Two patients underwent a sequencing .ב

test:

Patient A—The cells in Patient A's body produce an excess of protein A.

Patient B—The cells in Patient B's body produce protein A with an abnormal structure.

Determine for each patient whether their test found a change in nucleotide sequence in the

gene that encodes protein A or a change in the regulatory region of the gene that encodes

protein A. Explain your answer regarding each of the two patients.

(3 points)



Topic II — Developmental Comparative PhysiologyAnswer two questions: Question 34 (required) and one of the questions 35-36. The number of points is given at the end of each item.

Answer Question 34 (required).

.The following figures show two marine animals and the heart and respiratory organ of each .א .34

Animal אAnimal ב

(1) Determine which animal—א or ב—is a fish and which is a mammal. Explain your

answers.

In your answers, discuss both organs of each of the animals.

(2) List two properties that are common to the structure of the respiratory organ in mammals

and fish.

(4 points)

Marine mammals are able to stay underwater for much longer than terrestrial mammals that are .ב

capable of diving.

The following table shows data about a marine mammal and a terrestrial mammal.

Concentration of blood hemoglobin and inhalation-triggering concentration of blood CO2 in a marine mammal and in a terrestrial mammal

A BAverage concentration of blood

hemoglobin (gram/100 ml blood)

Concentration of blood CO2 which triggers inhalation

Marine mammal 24.6 high Terrestrial mammal 14.2 low

Suggest an explanation for the longer time that marine mammals can spend underwater:

(1) based on the data in Column A

(2) based on the data in Column B

(5 points)



Answer one of the questions 35-36.

and heart structure in [דו־חיים] List one difference between heart structure in amphibians (1) .א .35

reptiles [זוחלים].

(2) The difference in heart structure which you listed affects the extent that blood from the

two circulatory loops is mixed.

In which group, reptiles or amphibians, is the extent of mixing greater? Explain.

(3 points)

in its body [חילוף חומרים] When the skin of a frog (amphibian) loses moisture the metabolism .ב

cells also slows down. Explain why. (3 points)

Terrestrial mammals and birds of a similar size that inhabit similar environments lose different .א .36

quantities of water through their excretory system [מערכת ההפרשה].

The amount of water an organism [יצור] excretes is affected by the type of nitrogenous waste it

produces.

Copythefollowingtabletoyournotebookandfillinthemissinginformation.

(3 points)

Type of nitrogenous waste and quantity of water excreted by mammals and birds

Mammals

C o p y t o n o t e bo o kBirds

Type of nitrogenous wasteQuantity of water excreted (small/large)

The food of marine birds is rich in salt. These birds have salt glands at the front of their heads .ב

that excrete a concentrated salt solution to the environment.

Salt glands

Explain the importance of salt glands to the normal functioning of the body cells of marine

birds. (3 points)



Topic III: Bacteria and Viruses in the Human BodyAnswer two questions: Question 37 (required) and one of the questions 38-39. The number of points is given at the end of each item.

Answer Question 37 (required).37. Antibiotic substances are produced by fungi and bacteria. Type A bacteria produce the antibiotic

substance X. Graph 1 below describes a growth curve of Type A bacteria.

Graph 1: Number of bacteria over time

Time(hours)0

Number of live bacteriaper ml

(logarithmic scale)

Explain why the number of bacteria remained constant from t0 to t1 and why it remained .אconstant from t2 to t3, as shown in Graph 1. (3 points)

Graph 2 below shows the concentration of the antibiotic substance X during the growth of .בType A bacteria shown in Graph 1.

Graph 2: Concentration of the antibiotic substance X during bacterial growth

Time(hours)

Concentration ofsubstance X

(arbitrary units)

0

Explain why the concentration of the substance X continued to rise from t3 onward, even though the bacterial population was in the death phase. (2 points)

ATypeAllbacteria.ATypecontainedalreadythatflaskatoaddedwerebacteriaType B (1) .גbacteria were resistant to the antibiotic substance X, and all the Type B bacteria that were added to the container were sensitive to X. Afterawhile,TypeBbacteriathatwereresistanttoXwerefoundintheflask.Suggestanexplanationforthisfinding.

(2) The resistance of bacteria to substance X is caused by the activity of a certain bacterial cell protein. Suggest one possible mechanism of action by which a protein makes bacteria resistant.

(4 points)



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Answer one of the questions 38-39. 38. Some of the enzymes used in viral reproduction are synthesized according to the virus's own genetic

information and some are synthesized according to the host cell's genetic information. .The AIDS virus (HIV) contains a number of enzymes that it needs in order to reproduce .א

List the activity of one HIV enzyme which enters the host cell with the virus, and the activity of one enzyme that the virus needs to reproduce and which is synthesized according to the host cell's genetic information. (2.5 points)

two processes take place, I and II ,[נגיף הקורונה] After a cell is infected with COVID virus .ב(describedinthefigurebelow).

Viral RNA I

II

Viral protein

Viral RNA

Translation

RNA replication

(1) In which process, I or II, are the enzymes that catalyze the process not synthesized according to the host cell's genetic information? Explain your answer.

(2) Would you recommend using a substance that interferes with Process II as a medicine for this virus? Explain.

(3.5 points)

39. Viruses and bacteria can harm the human body.,virustheaboutinformationmissingtheinfillandnotebookyourtotablefollowingtheCopy .א

the bacteria, and the human cell (use the options provided in parentheses). (3 points)

C o p y t o n o t e b o o kVirus Bacteria Human cell

Nucleus membrane (yes/no)Mitochondria (yes/no) Cell wall (yes/no)Ribosomes (yes/no)Cellular respiration enzymes (yes/no)Genetic material (yes/no)

A person caught a herpes virus infection and became sick. After a while the disease symptoms .בdisappeared. A few years later, when this person had a fever, she had sores in the corners of her mouth. Such sores are caused by the herpes virus and are one of the symptoms of the disease.(1) Explain how the disease symptoms returned, even though the person was not exposed to

the virus again.(2) Could giving a passive vaccine immediately after the disease symptoms disappeared have

prevented the symptoms from recurring later? Explain.(3 points)

State of Israel ץיק דעומ Ministry of Education

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