LEVELS OF ORGANIZATION 2.1 describe the levels of organisation within organisms: organelles, cells, tissues, organs and systems.

Organisms are made from organizations of smaller structures. You need to know the following hierarchy of structures.

Organelles - intracellular structures that carry out specific functions within a cell

Cells - the basic structural and functional unit from which all biological organisms are made

Tissues - a group of specialized cells, which are adapted to carry out a specific function

Organs - a collection of two or more tissues, which carries out a specific function or functions

Organ Systems - a group of two or more organs

Nucleus Chloroplast Mitochondria Ribosome Vacuole

Neurone Skin cell Muscle cell Phagocyte Red Blood Cell

Muscle Nerves Blood Bone Adipose (Fat)

Heart Skin Brain Artery Kidney

Pulmonary Cardiac Nervous Endocrine Skeletal

LEVELS OF ORGANIZATION 2.1 describe the levels of organisation within organisms: organelles, cells, tissues, organs and systems.

CELL STRUCTURE (PLANT & ANIMAL) 2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole

You need to know the differences between plant and animal cells, the functions of the organelles and be able to recognize them in a microscope picture or drawing.

Mircroscope

CELL STRUCTURE (PLANT & ANIMAL) 2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole

CELL STRUCTURE (PLANT & ANIMAL) 2.3 describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole

Functions of the Organelles(These are the basic definitions you must know)

Cytoplasm - site of chemical reactions in the cell

Cell Membrane - controls what enters / leaves the cell (selectively permeable)

Nucleus - contains nucleic acids, which code for the synthesis of specific proteins. These proteins control all activity in the cell

Mitochondrion - site of respiration

Chloroplast - site of photosynthesis (contains chlorophyll)

Cell Wall - made from cellulose. Strengthens the cell and allows it to be turgid

Sap Vacuole - contains the cell sap. Acts as a store of water, or of sugars or, in some cases, of waste products the cell needs to excrete. Helps keep plant cell turgid.

PLANTS VS ANIMALS 2.4 compare the structures of plant and animal cells.

IF YOU ARE EVER ASKED TO DRAW AND LABLE A CELL IT MUST NOT BE A GENERAL CELL, BUT A SPECIFIC CELL

Cell theory

CELL STRUCTURE (PLANT & ANIMAL) 2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, chloroplast and vacuole

SOME SAMPLE CELL DIAGRAMS:

White blood cell

SPERM CELL

Root hair cell

CHEMICAL ELEMENTS OF ORGANIC MOLECULES 2.5 identify the chemical elements present in carbohydrates, proteins and lipids(fats and oils)

To be a basic organic molecule you must have: CHO

Some have: CHON or even CHONSCARBOHYDRATES PROTIENS LIPIDS

Carbon Carbon Carbon

Hydrogen Hydrogen Hydrogen

Oxygen Oxygen Oxygen

Nitrogen & Sulphur

CHEMICAL ELEMENTS OF ORGANIC MOLECULES 2.5 identify the chemical elements present in carbohydrates, proteins and lipids(fats and oils)

Making Complex Organic Structures (molecules) 2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar;

protein from amino acids; lipid from fatty acids and glycerol

Components of the main Food Groups:The main food groups are:1) Carbohydrate 2) Lipids (fats)3) Proteins

All three groups are polymers made from smaller molecules known as monomers.

1) Carbohydrates are large polymer molecules made from one or more monomer sugars.

Two carbohydrates you need to know are Starch and Glycogen. Both have glucose as their monomer. 2) Proteins are polymers of Amino Acids (there are 20 amino acids) 3) Lipid polymers are made from one glycerol molecule and three fatty acid molecules joined together. So lipids are made of two different types of monomers.

DEFINITIONS:Monomer: Single unitPolymer: Two or more monomers chemically combined together

Making Complex Organic Structures (molecules) 2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar;

protein from amino acids; lipid from fatty acids and glycerol

CARBOHYDRATE BONDS ARE CALLED:Glycosidic Bonds

Making Complex Organic Structures (molecules) 2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar;

protein from amino acids; lipid from fatty acids and glycerol

BONDS IN PROTEINS ARE CALLED:Peptide Bonds

Making Complex Organic Structures (molecules) 2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar;

protein from amino acids; lipid from fatty acids and glycerol

BONDS IN FATTY ACIDS AND GLYCEROL ARE CALLED:Ester Bond

REVIEW: Glucose is a Monomer of several Polymers

2.6 describe the structure of carbohydrates, proteins and lipids as largemolecules made up from smaller basic units: starch and glycogen from simple sugar; protein from amino acids; lipid from fatty acids and glycerol

Carbohydrate that is the chief form of stored energy in plants

Carbohydrate that is the main component of the cell walls of most plants

Carbohydrate is stored in the liver and muscles in man and animals

Making Cellulose(not required in your syllabus)

2.6 describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units: starch and glycogen from simple sugar; protein from amino acids; lipid from fatty acids and glycerol

Test for Glucose 2.7 describe the tests for glucose and starch

Benedict’s Test:

- In test tube with 2 ml of Benedict's reagent.- add 5-6 drops of the test carbohydrate

solution and mix well.- Place the test tube in a boiling water bath for

5 minutes. - Observe any change in color or precipitate

formation. - Cool the solution. - Observe the colour change from blue to green,

yellow, orange or red depending upon the amount of reducing sugar present in the test sample.

NEGATIVE TEST: Blue Solution (No change)POSITIVE TEST: Colour Precipitate (Change)

0.5% 1% 2%<x

Test for Starch 2.7 describe the tests for glucose and starch

Iodine Test:

- Add 2 drops of iodine solution to about 2 mL of the carbohydrate containing test solution.

- A blue-black colour is observed which is indicative of presence of starch.

NEGATIVE TEST: orange/brown Solution (No change)

POSITIVE TEST: Black Solution (Change)

Enzymes AKA Organic Catalysts 2.8 understand the role of enzymes as biological catalysts in metabolic reactions

1) Enzymes are large molecules that speed up the chemical reactions inside cells.

2) Enzymes have a specific job (break/make substances)

3) Enzymes are specific to a particular substrate (protein, carbohydrate, lipid)

4) Enzymes are a type of protein, and like all proteins, they are made from long chains of different amino acids.

5) Enzymes are not used up in the reactions they catalyze (speed up)

6) Enzymes are affected by temperature and pH

Enzymes are BIOLOGICAL CATALYSTS

hydrogen peroxide

Hydrogen peroxide breaks down to water and oxygen

The escaping oxygen causes the foaming

2H2O2 2H2O O2+

water + oxygenmanganese oxide

So What is an difference between an Inorganic Catalyst and an Enzyme

2.8 understand the role of enzymes as biological catalysts in metabolic reactions

• They occur inside cells or are secreted by the cells.• Catalase is the enzyme that catalyses the break

down of hydrogen peroxide.

So What is an difference between an Inorganic Catalyst and an Enzyme

2.8 understand the role of enzymes as biological catalysts in metabolic reactions

Catalase

To name an enzyme in most cases just add ‘-ase’ to the ending of the substrate.

Other special cases are:Specific proteases are Pepsin and Tripsin

Catalase increase the rate of H2O2 H20 + O2

Naming Enzymes2.8 understand the role of enzymes as biological catalysts in metabolic reactions

SUBSTRATE ENZYME

Protein Protease

Lipid (fats) Lipase

Maltose (disaccharide) Maltase

Carbohydrate Amylase (it used to be called Carbohydrase)

Enzymes AKA Organic Catalysts 2.8 understand the role of enzymes as biological catalysts in metabolic reactions

Enzymes are soluble protein molecules that can speed up chemical reactions in cells. These reactions include :• Respiration• Photosynthesis• Making new proteins

For this reason enzymes are called biological catalysts.

Enzymes AKA Organic Catalysts 2.8 understand the role of enzymes as biological catalysts in metabolic reactions

Each enzyme will only speed up one type of reaction as the shape of the enzyme molecule needs to match the shape of the molecule it reacts with (the substrate molecule). This is called the lock and key model.

The part of the enzyme molecule that matches the substrate is called the active site.

protein polypeptidestrypsin

white clear

Controlled variables:

•Volume and concentration of substrate (milk)•Volume and concentration of enzyme (trypsin)•pH (controlled by buffers)•Temperature

Rates of Enzymes 2.8 understand the role of enzymes as biological catalysts in metabolic reactions

Rates of enzyme reactions can be measured by recording the time for a substrate to disappear or a product to appear.

WHAT KIND OF UNITS WILL RATES OF

REACTION HAVE?

Temperature’s effect on Enzyme activity 2.9 understand how the functioning of enzymes can be affected by changes in temperature, including changes due to change in active site

At low temperatures, enzyme reactions are slow. They speed up as the temperature rises until an optimum temperature is reached. After this point the reaction will slow down and eventually stop.The enzyme activity increases as temperature increases because:1) More collisions between

substrate and enzymes2) More kinetic energy in each

collision between substrate and enzymes

3) More successful collisions because of 1 & 2.

The enzyme activity decreasing as temperature increases after a point because:1) Enzyme’s active site starts to change shape (denature)

Enzyme Activity against Temperature

RateOf Reaction

Temperature/oC0 10 20 3040 50 60 70

Optimum temperature

Enzyme is denaturingMolecules gain

kinetic energy

Temperature’s effect on Enzyme activity 2.9 understand how the functioning of enzymes can be affected by changes in temperature, including changes due to change in active site

If the shape of the enzyme changes, its active site may no longer work. We say the enzyme has been denatured. They can be denatured by high temperatures or extremes of pH. Note that it is wrong to say the enzyme has been killed. Although enzymes are made by living things, they are proteins, and not alive.

You can investigate the effect of temperature on the enzyme amylase using starch and iodine, putting the mixture in water baths at different temperatures.

pH’s effect on Enzyme activity 2.10 understand how the functioning of enzymes can be affected by changes in active site caused by changes in pH (TA)

Enzymes and pH

Most enzymes work fastest in neutral conditions. Making the solution more acid or alkaline will slow the reaction down. At extremes of pH the reaction will stop altogether.

Some enzymes, such as those used in digestion, are adapted to work faster in unusual pH conditions and may have an optimum pH of 2 (very acidic) if they act in the stomach.

pH’s effect on Enzyme activity 2.10 understand how the functioning of enzymes can be affected by changes in active site caused by changes in pH (TA)

Raising and lowering the pH can:• Make more hydrogen bonds or • Break hydrogen bonds These hydrogen bonds hold the protein’s active site in the correct shape

Experiments on Enzymes: TEMPERATURE 2.11 describe experiments to investigate how enzyme activity can be affected by changes in temperature.

Yeast and glucose solution vs Temperature.Measuring: CO2 produced (ml)

Amylase Iodine and Starch solutionIn different temperatures.Measuring: time for iodine test to be negative

Saliva and Starch solutionVs temperatureMeasuring: time for iodine test to become negative

Enzymes are used in biological washing powders

• Proteases break down the coloured, insoluble proteins that cause stains to smaller, colourless

soluble polypeptides. • Can wash at lower temperatures

POSSIBLE CORMMS QUESTIONS TOPICS 2.11 describe experiments to investigate how enzyme activity can be affected by changes in temperature.

Enzymes are used in the food industry• Pectinase break down substances in

apple cell walls and enable greater juice extraction.

• Lactase breaks down lactose in milk into glucose and galactose. This makes milk drinkable for lactose intolerant people.

Enzymes are used in seed germination

starch

embryo plantamylasesecreted

maltoseabsorbed

POSSIBLE CORMMS QUESTIONS TOPICS 2.11 describe experiments to investigate how enzyme activity can be affected by changes in temperature.

Key words

enzyme

active sitesubstrate product

denaturetemperature

pH

optimum

catalase amylase

trypsin pepsinpectinase

lactase

protease

catalyst catalyse protein

Movement into and out of a cellDEFINITIONS

2.12 understand definitions of diffusion, osmosis and active transport

Diffusion: The net movement of the particles of a gas or a solute from an area of high concentration to an area of low concentration down a concentration gradient.

Osmosis: The net movement of water down a concentrationgradient from an area of high concentration of water molecules to an area of low concentration of water moleculesacross a partially permeable membrane.

Active transport: The movement of substances against aconcentration gradient and/or across a cell membrane, usingenergy.

Movement into and out of a cellDiffusion

2.12 understand definitions of diffusion, osmosis and active transport

Diffusion: The net movement of the particles of a gas or a solute from an area of high concentration to an area of low concentration down a concentration gradient.

link

link

Movement into and out of a cellDiffusion

2.12 understand definitions of diffusion, osmosis and active transport

In Diffusion experiments you must only change one variable (IV), all other variables must be controlled. Examples are:

- Temperature (increases Kinetic energy)- Stirring (increases Kinetic energy)- Surface area of the boundary region- Thickness / distance molecules have to diffuse- The size of the concentration gradient- The surface area to volume ratio

Movement into and out of a cellOsmosis

2.12 understand definitions of diffusion, osmosis and active transport

Osmosis: The net movement of water down a concentration gradient from an area of high concentration of water molecules to an area of low concentration of water molecules across a partially permeable membrane.

Link

Movement into and out of a cellActive Transport

2.12 understand definitions of diffusion, osmosis and active transport

Active transport: The movement of substances against a concentration gradient and/or across a cell membrane, using energy. This also requires a carrier protein in the cell membrane.

link

Chemical energy is called ATP.

Movement into and out of a cellReview

2.13 understand that movement of substances into and out of cells can be by diffusion, osmosis and active transport

In cells molecules can move through the cell membrane by:

Diffusion: Small molecules move directly through the cell membrane from high concentration to low concentration. (NO ENERGY REQUIRED)Large molecules move through facilitated diffusion using protein channels from high concentration to low concentration. (NO ENERGY REQUIRED)

Osmosis:Water moves from high concentration to low concentration directly through the cell membrane. (NO ENERGY REQUIRED)

Active transport:Moves molecules and Ions through the cell membrane from low concentration to high concentration. (ENERGY REQUIRED, CARRIER PROTEIN REQUIRED)

TURGID CELLS

2.14 understand the importance in plants of turgid cells as a means of support (TA)

EXAMINATION POINTS (step by step)(4 Mark Question)

1) Plant cells are normally turgid (swollen full of water).

2) This is important because it provides strength to plants (rigidity).

3) Plant cells have a cell wall to stop them bursting when turgid.

4) When plant cells start to lose water they become flaccid.

5) Flaccid plants lose their strength and start to wilt.

6) Eventually, flaccid cells become plasmolysed as the cell membrane begins to peel away from the cell wall.

7) This kills the cell.

RBC Example (not in syllabus)

2.14 understand the importance in plants of turgid cells as a means of support (TA)

Variables affecting movement into and out of cells

2.15 understand the factors that affect the rate of movement of substances into and out of cells, to include the effects of surface area to volume ratio, temperature and concentration gradient

VARIABLES THAT AFFECT MOVEMENT RATE OF SUBSTANCES INTO AND OUT OF CELLS:

1) Temperature • As temperature increases movement increases • Eventually increased temperature ruptures the plasma membrane &

denatures the enzymes• killing the cell.

2) Concentration Gradient• The higher the concentration gradient of a substance the faster the

rate of diffusion• This is only if the substance can cross the plasma membrane

(osmosis/water)

3) Surface area/Volume ratio• (Next slide please)

Variables affecting movement into and out of cells

2.15 understand the factors that affect the rate of movement of substances into and out of cells, to include the effects of surface area to volume ratio, temperature and concentration gradient

If the surface area to volume ratio is too small1) Living cell can not get nutrients for respiration and growth.2) Living cells can not remove waste before toxins build up. 3) Cell size is limited by diffusion.

Variables affecting movement into and out of cells

2.15 understand the factors that affect the rate of movement of substances into and out of cells, to include the effects of surface area to volume ratio, temperature and concentration gradient

WHAT IS THE SURFACE TO VOLUME RATIO’S FOR THESE TWO CELLS?

Variables affecting movement into and out of cells

2.15 understand the factors that affect the rate of movement of substances into and out of cells, to include the effects of surface area to volume ratio, temperature and concentration gradient

CORMMS QUESTION: Design an experiment that shows how the surface area to volume ratio affects diffusion in agar cubes using a solution of Phenolphthalien (a type of dye).

C:O:R:M:M:S:

Experiments on Diffusion and Osmosis

2.16 describe experiments to investigate diffusion and osmosis using living and non-living systems.

Good examples of diffusion are: - Ink chromatography- The diffusion of KMnO4 crystals (purple) into water- Diffusion of gases in the lung- Diffusion of gases in the leaf - Gas diffusion of Bromine gas

Osmosis can be shown by:- Artificially using visking tubing- Potato chips in salt solutions of different concentrations.