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Cell Cell Structure Structure

and and FunctionFunction

Part 2Part 2Prokaryotes and Eukaryotes Prokaryotes and Eukaryotes Characteristics of Living ThingsCharacteristics of Living Things

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Prokaryotes vs. Prokaryotes vs. EukaryotesEukaryotes

• Almost all the cells we have been learning about are from higher Almost all the cells we have been learning about are from higher organisms like plants and animals. We call these organisms like plants and animals. We call these ______________________cells, cells, meaning “meaning “true nucleustrue nucleus.” .”

• They are organized into different compartments (_________) They are organized into different compartments (_________) including the nucleus, each with a different function. including the nucleus, each with a different function.

• Many of these are separated from the rest the cell by their own Many of these are separated from the rest the cell by their own ___________. ___________.

• There are There are TWOTWO types of cells, though. Long before there were types of cells, though. Long before there were eukaryotes, there were much simpler organisms (usually single-eukaryotes, there were much simpler organisms (usually single-celled) called celled) called ____________________________..

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Early Life, Primitive Early Life, Primitive LifeLife

For the first ___________ years of Earth’s history, For the first ___________ years of Earth’s history, though, there were no organisms with eukaryote cells. though, there were no organisms with eukaryote cells. In fact, most life consisted of very primitive (and In fact, most life consisted of very primitive (and usually single-celled) organisms. Some of these, such usually single-celled) organisms. Some of these, such as the many types of bacteria and blue-green algae, as the many types of bacteria and blue-green algae, still exist today. Their cells are much less complicated still exist today. Their cells are much less complicated than eukaryote cells. than eukaryote cells. _________________________._________________________. These These types of cells are called ____________ cells, for “types of cells are called ____________ cells, for “before before nucleusnucleus”. ”.

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Prokaryote Cell Prokaryote Cell StructureStructure

• Prokaryote cells are too small to see much Prokaryote cells are too small to see much structure under a normal microscope. We can see structure under a normal microscope. We can see more detail with an _______ microscope, since that more detail with an _______ microscope, since that magnifies much more than light microscopes do. magnifies much more than light microscopes do.

• Prokaryotes do have a cell ___________, a _________, Prokaryotes do have a cell ___________, a _________, and cytoplasm, and they contain _______ (usually a and cytoplasm, and they contain _______ (usually a circular chromosome) circular chromosome) but they do not have a but they do not have a nucleus or organelles.nucleus or organelles. They do much of the same They do much of the same chemistry as eukaryotic cells, but these functions chemistry as eukaryotic cells, but these functions are not in separate compartments.are not in separate compartments.

• Most prokaryotic organisms are _______________. Most prokaryotic organisms are _______________.

• On average, they are _________ the size of On average, they are _________ the size of eukaryote cells. eukaryote cells.

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Prokaryote (bacteria) cell structureProkaryote (bacteria) cell structure

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Comparison of __________ Comparison of __________ and ___________ Cellsand ___________ Cells

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ExamplesExamples

Is yeast a eukaryote or prokaryote? How can you tell?Is yeast a eukaryote or prokaryote? How can you tell?What about Cyanobacteria (aka blue-green algae)?What about Cyanobacteria (aka blue-green algae)?

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ComparisonsComparisons

Archaea (aka archaeabacteria) are a group of ______________ that in many ways Archaea (aka archaeabacteria) are a group of ______________ that in many ways are as different from the true Bacteria as they are from Eukaryotes. Many of them are as different from the true Bacteria as they are from Eukaryotes. Many of them are found in ______________________, such as Yellowstone National Park’s hot are found in ______________________, such as Yellowstone National Park’s hot springs, or deep ocean thermal vents. (Prokaryotes = ______________________)springs, or deep ocean thermal vents. (Prokaryotes = ______________________)

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Examples - True Examples - True bacteriabacteria

Escherichia coli (E. coli)Escherichia coli (E. coli)

Under high magnification Under high magnification with a ________________with a ________________

Under high magnification Under high magnification with an ______________with an ______________

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Mycobacterium tuberculosisMycobacterium tuberculosisCauses __________Causes __________

Streptococcus pneumoniaeStreptococcus pneumoniaeCauses _____ infectionsCauses _____ infections

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What is Life?What is Life?

• Prokaryotes and eukaryotes are the two main Prokaryotes and eukaryotes are the two main divisions of life. But what is required for divisions of life. But what is required for something to be alive?something to be alive?

• As a biological ___________ we can say living As a biological ___________ we can say living things:things:– Are made of cellsAre made of cells– Can reproduce on their ownCan reproduce on their own– Are based on a universal genetic code (DNA)Are based on a universal genetic code (DNA)– Grow and developGrow and develop– Obtain and use materials and energyObtain and use materials and energy– Respond to their environmentRespond to their environment– Maintain a stable internal environmentMaintain a stable internal environment– Change over time, when taken as a groupChange over time, when taken as a group

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As we have seen, cells are the basic building blocks of life. We can As we have seen, cells are the basic building blocks of life. We can break cells down to smaller parts, but those parts are not alive. break cells down to smaller parts, but those parts are not alive.

Some organisms are a single cell by itself. These are Some organisms are a single cell by itself. These are unicellularunicellular (uni = _____) organisms. Others (like us) are (uni = _____) organisms. Others (like us) are multicellular multicellular (multi = (multi = _____), and may be made of billions of cells. _____), and may be made of billions of cells.

1. Living things are made of ____.1. Living things are made of ____.

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All living organisms produce new All living organisms produce new organisms through the process of organisms through the process of reproduction. reproduction.

Most use Most use ____________________________________, where , where cells from two parents combine to form the cells from two parents combine to form the new organism. new organism.

In many cases, though, the new organism In many cases, though, the new organism only has a single parent. This is called only has a single parent. This is called asexualasexual (____________) (____________) reproductionreproduction. . Offspring are copies of the parent.Offspring are copies of the parent.

Examples of asexual reproduction: Examples of asexual reproduction: Bacteria __________ to form two new Bacteria __________ to form two new bacterial cells. Hydra budding (at left)bacterial cells. Hydra budding (at left)

A Hydra undergoing A Hydra undergoing asexual reproduction. asexual reproduction. New buds (#3, above)New buds (#3, above)

2. Living things ____________.2. Living things ____________.

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3. Living things are based on a 3. Living things are based on a universal genetic code.universal genetic code.

Offspring always resemble their parents, so there is some way that information Offspring always resemble their parents, so there is some way that information is _______________________________. That information is in the genetic code. is _______________________________. That information is in the genetic code. The same code (with a few minor exceptions) is used for _____ living organisms. The same code (with a few minor exceptions) is used for _____ living organisms.

In cases of asexual reproduction, In cases of asexual reproduction, the offspring has the _____________ as the the offspring has the _____________ as the parent, so it is in many ways just a new copy of the parent.parent, so it is in many ways just a new copy of the parent.

With sexual reproduction, the genetic code of the parents is mixed (_________) With sexual reproduction, the genetic code of the parents is mixed (_________) and the offspring is not identical to the parents. and the offspring is not identical to the parents. The offspring will share some traits The offspring will share some traits with each parent, but will be _________. with each parent, but will be _________.

The genetic code is based on The genetic code is based on ________________ (deoxyribonucleic acid) and (deoxyribonucleic acid) and __________ (ribonucleic acid). This essentially contains all the information needed to build a (ribonucleic acid). This essentially contains all the information needed to build a new organism. It is not only a program for what proteins are needed, but also when new organism. It is not only a program for what proteins are needed, but also when and how to make them.and how to make them.

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All living things have a particular All living things have a particular __________________________ that __________________________ that occurs over their lifetime – their occurs over their lifetime – their life life cyclecycle..

Some organisms _______________ Some organisms _______________ without really changing over their without really changing over their lifespan. lifespan.

Many organisms start as a single-celled Many organisms start as a single-celled embryo and _______ (changing form, embryo and _______ (changing form, sometimes in several distinct stages) into sometimes in several distinct stages) into an adult. As adults, they reproduce, and an adult. As adults, they reproduce, and start a new generation.start a new generation.

During development, cells not only get During development, cells not only get larger, but they larger, but they ______________________ (become (become different types, with different purposes).different types, with different purposes).

4. Living things grow and develop. 4. Living things grow and develop.

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• Growth and development Growth and development require raw require raw materials and energymaterials and energy. Plants get the raw . Plants get the raw materials they need from the soil and air, and materials they need from the soil and air, and get energy ____________ by get energy ____________ by photosynthesisphotosynthesis. .

• Animals get these materials by ________ on Animals get these materials by ________ on plants and other animals. They get energy by plants and other animals. They get energy by eating plants (or eating other animals that ate eating plants (or eating other animals that ate plants) that have stored the sun’s energy. plants) that have stored the sun’s energy.

•The sun is the The sun is the source of energysource of energy for almost all for almost all living things. living things.

• Organisms break down or build up these Organisms break down or build up these materials by _________ processes known as materials by _________ processes known as metabolismmetabolism. .

5. Living things need materials 5. Living things need materials and ________.and ________.

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• All living things are exposed to a constantly changing All living things are exposed to a constantly changing _____________. Temperatures, sunlight, water, or other factors may _____________. Temperatures, sunlight, water, or other factors may change on an hourly, daily, or yearly cycle. change on an hourly, daily, or yearly cycle.

• All organisms respond in their own way to these changes. Many All organisms respond in their own way to these changes. Many times, these changes may be important in the lifecycle of the times, these changes may be important in the lifecycle of the organism. For instance, many plants require __________________ organism. For instance, many plants require __________________ dark hours at night (or certain temperatures) before they will bloom.dark hours at night (or certain temperatures) before they will bloom. • Many organisms may make __________ to their environment. Many organisms may make __________ to their environment.

6. Living things ________ to their 6. Living things ________ to their environment.environment.

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Despite constant changes in the external environment, the Despite constant changes in the external environment, the conditions on the inside of an organism need to _____ conditions on the inside of an organism need to _____ __________. It may take in water and food and eliminate __________. It may take in water and food and eliminate waste, but the overall amount of water, overall waste, but the overall amount of water, overall temperature, etc., need to stay the same. temperature, etc., need to stay the same.

This This __________________________________________________ to keep things stable to keep things stable is called is called homeostasis (“self-stable”)homeostasis (“self-stable”). Most living things . Most living things have a fairly ______ range of internal conditions they can have a fairly ______ range of internal conditions they can tolerate. If homeostasis is disrupted too much, the tolerate. If homeostasis is disrupted too much, the organism may die. Frequently, external temperature, etc., organism may die. Frequently, external temperature, etc., are important only in how they affect the internal are important only in how they affect the internal conditions. conditions.

7. Living things maintain a stable ________ 7. Living things maintain a stable ________ environment.environment.

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From one generation to the next these changes are _____________________, but From one generation to the next these changes are _____________________, but over hundreds or even millions of generations they add up to big changes. If the over hundreds or even millions of generations they add up to big changes. If the environment the organism is living in alters drastically, some may have changed in environment the organism is living in alters drastically, some may have changed in ways that allow them to survive and pass their traits on to future generations. Those ways that allow them to survive and pass their traits on to future generations. Those that weren’t able to survive ________________. that weren’t able to survive ________________.

As an example: most of the plants we see in the Sonoran Desert did not originally As an example: most of the plants we see in the Sonoran Desert did not originally develop in desert areas, but they were able to ___________________ to conditions develop in desert areas, but they were able to ___________________ to conditions when the climate changed and the desert arose. Some have changed enough that when the climate changed and the desert arose. Some have changed enough that they don’t survive outside the desert. they don’t survive outside the desert.

8. Groups of living things evolve.8. Groups of living things evolve.

An organism changes as it ages, but the An organism changes as it ages, but the basic traits it inherited from its parents basic traits it inherited from its parents usually do not change. As a group, though, usually do not change. As a group, though, any kind of organism can any kind of organism can _____________ _____________ _________ (evolve)._________ (evolve).