1. Fundamental Biology

Characteristics of living organisms

MRS GREN C

• movement

• Respiration

• Sensitivity

• Growth

• Reproduction

• Excretion

• Nutrients

• Control

MRS GREN C : M

Movement : ability to change position in ways such as tilting, walking or swimming

MRS GREN C : R

Reproduction : ability to have children/offspring and pass genes down to them

MRS GREN C : S

Sensitivity : ability to take in information from surroundings

MRS GREN C : G

Growth : abiltiy to use nutrients that they have taken in to get larger

MRS GREN C : R

Respiration : ability to use nutrients that they’ve taken in to produce energy for movement, keeping warm and other bodily processes

MRS GREN C : E

Excretion : abiltiy to get rid of waste products

MRS GREN C : N

Nutrition : abiltiy to take in nutrients by eating or absorbing

MRS GREN C : C

Control : abiltiy to control internal conditions (e.g temperature, water levels, chemical balance)

Single celled organism VS multi-celled organism

Single : just one cell

Multi : multiple cells that have different systems for exchanging and transporting materials (AT)

Cell Organisation

Cells → Tissues → Organs → Organ System → Organism

Cell

Basic functional and structural units in a living organism

Tissue

Groups of cells of similar structure working together to perform a particular function (can include more than one type of cell)

Organ

Group of different tissues working together to perform a certain function

Organ system

A group of organs working together to perform a particular function

Organism

Different organ systems working together

How to observe cells under a microscope

1. Pull inner layer off

2. Place layer in the centre of slide

3. Place 2 drops of iodine on to the slide

4. Lower the cover slip

5. Observe under the microscope

Conversion between cm, mm, and µm

Magnification formula

Magnificat = image size / actual size

Subcellular structures in animal cells :

1. Nucleus

2. Cytoplasm

3. Cell membrane

4. Mitochondria

5. Ribosomes

Subcellular structure in a plant cell

1. Nucleus

2. Cytoplasm

3. Cell membrane

4. Mitochondria

5. Ribosomes

6. Cell wall

7. Permanent vacuole

8. Chloroplasts

Function : nucleus

Contains genetic material that controls activities of cell

Function : cytoplasm

Gel-like substance where most of the chemical reactions happen - has enzymes that control these reactions

Function - cell membrane

Holds the cell together and controls what goes in and out

Function : mitochondria

Where most of the reactions for aerobic respiration take place

Function : ribosomes

Where protein synthesis occurs (protein is made)

Function : cell wall (plant)

Made of cellulose and supports the cell and strengthens it

Function : permanent vacuole (plant)

Stores cell sap, a weak solution of sugar and salts and helps maintain the rigidity of the cell

Function : chloroplasts (plant)

Contains chlorophyll (which absorbs light needed for photosynthesis), where photosynthesis occurs

Respiration

≠ breathing (mechanical process)

The process of transferring energy from the breakdown of glucose to cells in the body

Aerobic respiration

Respiraiton using oxygen, the most efficient way to transfer energy from glucose and occurs inthe mitochondria

Glucose + oxygen → Carbon Dioxide + water

C6H12O6 + 6O2 → 6CO2 + 6H20

Anaerobic respiration

Without the presence of oxygen and is an incomplete breakdown of glucose, making lactic acid. This makes less energy than aerobic respiration as glucose isnt fully oxidised

Glucose → Lactic Acid

C6H12O6 → C3H6O3

Anaerobic respiration in plants and yeast

Glucose → ethanol + carbon dioxide

C6H12O6 → 2C2H5OH + 2CO2

When respiraiton occurs, what is produced

ATP, which provides energy for cells

CP 7 : respiration, heat

Investigate the heat production in respiring cells

CP 7 : respiration, carbon dioxide

Investigate the production of carbon dioxide in respiring cells using hydrogen carbonate indicator solution

CP 7 : respirometer

1. Set up the respirometer as shown in the diagrem

2. Use the syringe and 2 way tap to move the coloured liquid

3. Make sure the bung is pushed in securely

4. Record the start position and start a timer for 5 min

5. Record the end position of the coloured liquid

6. Calculate rate of respiration through : Volume of oxygen used /time

Anaerobic Respiration Practical

1. Use 600cm cubed beaker to make a water bath at 40°

2. Fill one boiling tube with limewater qnd the other with 2.5g of yeast and 25ml of 10% glucose solution

3. Stir and wait 1 minute

4. Place the boiling tube of yeast and glucose into the water bath and match the temperature to what is appropriate

5. Use a pipette to add enough cooking oil to cover the surface of the yeast glucose mixture

6. Fix the delivery tube to the boiling tube with limewater, start the clock and count the number of bubbles produced in 1 minute

7. Change the temperature and repeat the steps to test different temperature

What is downward displacement

Using a water filled measuring cylinder rather than counting bubbles to measure the volume of gas

Anaerobic respiration in yeast cells is known as..

Fermentation

Yogurt production

1. Milk is pasteurised at 85-90°C for 15-30 min to kill existing disease or microorganism

2. Milk is homogenized (breaking down fat globules into smaller particles to prevent cream from separating)

3. Milk is cooled to 40-45°C and lactobacillus is added (avoid killing lactobacillus and reaching the optimum temperature)

4. The mixture is incubated for a few hours and the lactobacillus digests the lactose found in the milk into lactic acid

5. The yogurt thickens and is cooled

Features of a plant

1. Multicellular

2. Have cell walls made of cellulose

3. Have chlorophyll in chloroplasts

4. Can photosynthesise (autotrophs) and store glucose as starch/sucrose in chloroplasts

5. No nervous coordination, meaning they cant move from 1 place to another on their own

Features of animals

1. Multicellular

2. Do not have a cell walls made, chlorophyll, chloroplasts

3. Cannot photosynthesize, so rely on feeding (heterotrophs) to store glucose as glycogen

4. Have nervous coordination

5. Can move from one place to another on its own

Role of yeast in making bread

The yeast respires anaerobically and produces carbon dioxide and ethanol. The carbon dioxide gets trapped in the dough causing it to rise (and have pockets)

Role of yeast in beer production

The yeast respires anaerobically, reacting with the glucose (from barley), forming ethanol and carbon dioxide

Diffusion

The movement of particles from an area of high concentration to an area of low concentration

• occurs in both gases and solutions

What affects rate of diffusion and osmosis

1. Temperature

2. Concentration gradient

3. Surface area to volume ratio

4. Distance

Osmosis

Movement of water from an area of high water potential (low concentration) to an area of low water potential (high concentration) through a semi-permeable membrane

Hypertonic, isotonic, hypotonic solutions and cells

Hypertonic : high solute concentration/low water potential : cells become flaccid/shriveled

Isotonic : the same concentration : cells remain normal

Hypotonic : a low solute concentration/high water potential : cells become turgid (and could pop)/lysed

Active Transport

Movement of particles through protein pumps/carriers from a region of lower concentration to higher concentration against a concentration gradient, using energy from respiraiton

E.g : root hair cells, in the gut

What is visking tubing

A tube that has microscopic holes (that let some molecules like water to pass through but not larger molecules), making it partially permeable