Random biology past paper questions

Describe the process of cloning an adult animal using a named example (6)

1. Dolly

2. Nucleus (containing DNA) removed from desired parent animal

3. Nucleus and enculeated egg shell fused with electric shock

4. Mitosis

5. Producing embryo

6. Implanted into uterus

7. Of surrogate mother

Describe the role of insulin (2)

1. Lower blood glucose/convert blood glucose

2. To glycogen

3. Stored in muscles/liver

Describe how bacteria are genetically modified to produce human insulin (3)

1. Human gene for insulin

2. (cut with) restriction enzyme

3. (join with) ligase

4. vector/plasmid

Explain why a fermenter is cleaned using steam before GMO bacteria are added (3)

1. Aseptic conditions/sterilise

2. Remove other pathogens/bacteria

3. Reduce competition

4. Reduce contamination

5. Leaves no residue

Suggest why many eggs are needed for cloning to be successful (2)

1. Not all eggs survive

2. Not all embryos implant

Explain how to set up a potometer to measure water loss (4)

1. Cut plant under water

2. Seal connection (airtight)

3. Air bubble

4. Measure distance

5. Use reservoir (to measure volume)

Discuss what effect a change in the sequence of bases could have on the functioning of the enzyme produced (4)

1. (deletion/insertion) may change amino acid sequence

2. (change shape of) active site

3. Enzyme does not bind with substrate

4. Enzyme does not function

1. Some codons may code for same amino acid

2. Not all changes in bases alter amino acids

3. Only one amino acid changes in protein

4. Enzyme still functions

Explain how very warm weather results in a change in the concentration and volume of the urine (4)

1. Increased sweat

2. Blood concentration increases

3. More ADH

4. From pituitary gland

5. More water reabsorbed from collecting duct

6. Lower volume/more concentrated urine

Explain how vaccination reduces risk of infection (3)

1. Inactive pathogen

2. antigens

3. memory cells

4. secondary immune response

5. antibody production faster

Explain why transpiration is useful for plants (2)

1. Draws water up (to leaves)

2. Cooling

3. Transports minerals

4. Prevent wilting

5. (water for) photosynthesis

Explain why using stem cells from the same person is better than using stem cells from a different person (2)

1. Cells have same DNA

2. Same antigens

3. Less risk of rejection

4. No immune response

5. No risk of infection

Describe the differences between the processes of transcription and translation (5)

1. Transcription occurs in nucleus

2. Transcription uses DNA to make RNA

3. DNA unzips

4. Transcription makes mRNA

1. Translation occurs at ribosomes

2. Translation involves mRNA and tRNA

3. Anticodons bind to codons

4. Translation produces polypeptide chain

Describe the function of paddles in a fermenter (2)

1. Mix microorganisms with food substrates

2. Mix oxygen

3. Distribute heat

Describe the role of FSH (2)

1. Stimulates development of egg

2. Stimulates oestrogen release

Describe the role of LH (2)

1. Stimulates release of progesterone

2. Stimulates egg release

3. Stimulates development of corpus luteum

4. Inhibits release of oestrogen

Explain why blocked tubes leading from the mouth can lead to death in animals (5)

1. Less food taken in

2. Less digestion

3. Fewer amino acids / less glucose

4. Less gas exchange

5. Less oxygen (in blood)

6. Less carbon dioxide removed

7. Less (aerobic) respiration

8. Less energy

Describe what happens in the translation stage of protein synthesis (4)

1. (mRNA arrives at) ribosome

2. mRNA has codons

3. Ribosome moves along mRNA strand

4. tRNA brings amino acids (to ribosome)

5. anticodon (on tRNA) binds with codon (on mRNA)

6. Amino acid chain produced / amino acid joined / polypeptide

Explain why scientists want to conserve endangered plant species (2)

1. Maintain biodiversity

2. Prevent extinction

3. Medicinal properties

4. In case climate changes

Explain why the pH of culture media needs to be kept constant (3)

1. Enzyme affected by pH

2. Shape of active site changed

3. Enzyme denatured

Describe an experiment to show the phototropic response of plant stems to light (3)

1. Shoot in light from one side

2. Shoot in darkness OR light all around

3. Leave both for stated time

4. Bend towards light

Describe a calorimetry experiment (4)

1. Measure out volume of water

2. Use sample of food of the same mass

3. Hold under boiling tube of water

4. Continue until completely burnt

5. (Use thermometer) to measure increase in water temperature

6. Highest temperature rise

Describe how pollution by fertiliser can affect aquatic ecosystems (5)

1. Increase in nitrates

2. Eutrophication

3. Algal bloom

4. Blocks sunlight

5. Plants die

6. Bacteria decompose

7. Oxygen depleted

8. Fish die

Describe the consequences of smoking cigarettes for the functioning of the lungs

1. Destroys cilia in trachea

2. Mucus builds up

3. Leads to (bacterial) infection (of alveoli)

4. Loss of surface area

5. Airways inflamed/bronchitis

6. Can lead to COPD

7. Lung cancer

Describe the role of the stomach (3)

1. Protease

2. Breaks down protein

3. Hydrochloric acid

4. Kills pathogens

5. Churning

Explain the changes that occur in the structures of the eye that allow light from a distant object to be focused on the fovea (4)

1. Ciliary muscles relax

2. Suspensory ligaments tighten

3. Lens thinner

4. Light less refracted

5. Pupil dilates

Give two reasons why not all energy is transferred between trophic levels (2)

1. Respiration

2. Uneaten

3. Cannot be digested

4. Excretion

Give two differences in structure between red and white blood cells

1. RBCs have no nucleus

2. RBCs are smaller

3. RBCs are biconcave

Describe the role of the diaphragm and the intercostal muscles in inhalation (4)

1. Diaphragm contracts

2. Diaphragm flattens

3. (External) intercostal muscles contract

4. Rib cage raised

5. Volume (of chest cavity/thorax) increases

6. Pressure in (chest cavity/thorax) decreases

7. Air drawn into lungs

Describe how a saprotrophic fungus such as mould obtains its food (3)

• Enzymes

• (feed on) dead/decaying organisms

• For extracellular digestion

• Absorb digested food

Explain why there is a greater variation in height of the cattle than there is in hair colour (2)

• Height is polygenic

• Multiple genes control height

• Animals may get a mixture of dominant and recessive alleles for different genes

• Environment/nutrition may affect height

Describe the role of microorganisms in the conversion of organic waste into nitrate ions in the river (3)

• Decomposition

• Bacteria / fungi

• (Organic waste) to ammonia / ammonification

• Ammonium to nitrite / nitrite converted to nitrate

• Nitrification

Explain the differences between the palisade mesophyll and the spongy mesophyll (4)

• Palisade at top OR spongy in middle

• Palisade closely packed OR spongy have air spaces

• Palisade have more/many chloroplasts

• Palisade cells absorb light (1)

• Spongy allow diffusion / transpiration

Describe how a protein is made in a cell (5)

• Transcription

• mRNA leaves nucleus

• Ribosomes

• tRNA(brings) attached amino acids

• codons / anticodons

• Translation

Many alveoli increase the surface area, which will increase the rate of diffusion. Explain three other ways that alveoli are adapted to maximise gas exchange (3)

• One cell thick and short diffusion distance

• Moist and gases dissolve / in solution

• Capillaries and concentration gradient