Biology Paper 2

Question 1

Describe how you test a leaf for starch

Answer 1

Place leaf in hot ethanol in water bath
Use iodine solution
If starch present = leaf goes blue/black

Question 2

Structure of Palisade Mesophyll

Answer 2

Cells tightly packed/elongated
Cell contain chloroplasts
Palisade mesophyll contains lots of chloroplasts
Chlorophyll absorb sunlight for photosynthesis

Question 3

Structure of Spongy Mesophyll

Answer 3

Contains air spaces and gaps
Spongy cells are irregularly arranged
Diffusion occurs in spongy mesophyll
Spongy mesophyll in lower surface of leaf

Question 4

Where is stomata on surface of a leaf

Answer 4

In lower surface of leaf
No stomata in upper surface

Question 5

How is protein made in a cell

Answer 5

Transcription occurs
mRNA leaves nucleus
Enters cytoplasm and ribosomes
tRNA bring attached amino acids
For complementary base pairing
Translation occurs

Question 6

Where does ultrafiltration take place in nephron

Answer 6

Bowman’s capsule

Question 7

Where does reabsorption of glucose take place in nephron

Answer 7

PCT

Question 8

Which part of nephron responds to a change in ADH

Answer 8

Collecting Duct

Question 9

Function of collecting duct

Answer 9

Water reabsorbed
via osmosis
So less water in urine

Question 10

FSH function

Answer 10

Pituitary gland: Stimulates follicle growth
Lowest peak on a graph

Question 11

LH function

Answer 11

Pituitary gland: Ovulation
Highest peak on graph

Question 12

Oestrogen function

Answer 12

Ovary: Repairs uterus lining
Peak left of highest peak on graph

Question 13

Progesterone function

Answer 13

Ovary: Maintains uterus lining
Highest peak at day 21 on a graph

Question 14

4 ways alveoli adapted for maximum gas exchange

Answer 14

1 cell thick
High concentration gradient
Contain moisture and water
High surface area to volume ratio

Question 15

Give a method to sterilise without killing cells

Answer 15

Alcohol

Question 16

Why can’t animal tissue grow into new individuals via micropropagation

Answer 16

Cells are specialised
Only one cell type present
No stem cells present

Question 17

Describe how the nephron absorbs glucose back into the blood from
the filtrate.

Answer 17

Selective reabsorption
In PCT
Via active transport

Question 18

Tube transporting
urine to bladder

Answer 18

Ureter

Question 19

Explain how the pituitary gland and the nephron cells will
respond in a patient who is dehydrated

Answer 19

Lower Water Potential in Blood
Pituitary gland release more ADH
Collecting duct more permeable
More water reabsorbed
Urine more concentrated

Question 20

Label A,B,C,D,X

Answer 20

A = Retina
B = Conjunctiva
C = Cornea
D = Lens
X = Iris

Question 21

Eye in Bright Room

Answer 21

Circular muscles contract
Radial muscles relax
Pupil constricts

Question 22

Describe how a farmer could use selective breeding to increase the height
of cattle.

Answer 22

Select cattle that taller and mate them
Select offspring taller and mate them
Repeat through generations

Question 23

Explain why micropropagation was used to produce copies of the transgenic
soya plant.

Answer 23

Plants genetically identical
All have same of (specific characteristic)
Fast Method

Question 24

Explain energy content practical

Answer 24

Ignite chip and hold under test tube
Keep igniting till chip burnt completely
Measure Change in Temp
Repeat three times
Same mass of banana chips
Same volume of water

Question 25

Insulation prevents...

Answer 25

heat loss

Question 26

Oxygen supplies ensure...

Answer 26

complete combustion occurs

Question 27

Explain the negative effects of an increase in atmospheric carbon dioxide gas

Answer 27

Cause greenhouse effect Ice cap melting Ocean acidification

Question 28

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

Answer 28

Decomposers Convert organic waste to ammonia Nitrification occurs Convert nitrites into nitrates

Question 29

Which groups of microorganisms include pathogens

Answer 29

bacteria, fungi, protoctista and virus

Question 30

Explain how the rabies vaccine prevents dogs from developing rabies

Answer 30

Antigens in vaccine Lymphocytes recognise antigens Memory Cells made So antibodies made faster when virus encountered

Question 31

Describe how the cells use the RNA to produce the viral proteins

Answer 31

Ribosomes bind to DNA Translation occurs Codon on RNA codes for amino acid tRNA binds to RNA tRNA brings amino acids Amino acids join together to make protein

Question 32

Explain why producing genetically engineered plants with additional suberin in their roots could reduce atmospheric carbon dioxide

Answer 32

Plants absorb CO2 For photosynthesis CO2 stored as suberin Less CO2 released from decomposition

Question 33

Transgenic means

Answer 33

Cell/Organism undergone genetic modification - genes transferred from unrelated organism

Question 34

Give three reasons why the scientists use micropropagation to reproduce the transgenic crop plants

Answer 34

Prevent water loss Due to osmosis When water moves from high to low water potential

Question 35

Suggest why the student poured water through the soil samples for five minutes before adding the ammonium salts

Answer 35

Wash away nitrate Nitrate made from ammonium salt So test is fair

Question 36

In nephron protein doesn't pass out of what?

Answer 36

Glomerulus Too large

Question 37

Beta thalassaemia is a genetic condition caused by a mutation in a gene for haemoglobin. People with beta thalassaemia produce less haemoglobin and fewer red blood cells than people without the condition. (a) Explain why people with beta thalassaemia may experience severe tiredness.

Answer 37

Less oxygen transported to muscles Less respiration

Question 38

DNA strand

Answer 38

A-T C-G

Question 38

DNA-RNA strand

Answer 38

A-U C-G

Question 39

Protein synthesis of the modified gene will produce haemoglobin. Describe the stages of this protein synthesis

Answer 39

Transcription occurs in nucleus Production of mRNA Translation occurs - mRNA bind to ribosome tRNA brings amino acids Codon binds to anticodon Triplets on tRNA and mRNA bind

Question 40

Enucleated Meaning

Answer 40

Nucleus Removed

Question 41

Explain importance of cell differentiation in development of growing embryo

Answer 41

Unspecialised cells develop into specialised cells Cells with specific functions To produce tissues/organs

Question 42

Explain issues between adult stem cells and embryonic stem cells for treatment

Answer 42

Cells from embryo can make any cell type Ethical issues from using embryonic stem cells

Question 43

Describe role of bacteria in nitrogen cycle

Answer 43

Nitrogen Fixation - nitrogen gas to ammonia Nitrification - Nitrite to Nitrate And Ammonia to Nitrite Denitrification - Nitrate to Nitrogen Gas

Question 44

Describe how mammal is cloned

Answer 44

Use enucleated egg Fuse adult cell with empty egg Use of electricity for shock Cell division mitosis occurs Forms embryo Place in uterus womb of surrogate mother

Question 45

Eye far object

Answer 45

Ciliary muscles relax Suspensory ligaments Refracts by smaller amount