wrong bio ppq's

Question 1

which bond joins monosaccharides 2gether?

Answer 1

glycosidic

Question 2

Which ions are:
-cofactor for amylase
- prosthetic group for carbonic anhydrase

Answer 2

Cl-, Zn2+

Question 3

Describe process of inhalation

Answer 3

• ribcage moves up and out
• EIM’s contract
• Diaphragm contracts

Question 4

How do u know when ventricular systole is happening on a graph?

Answer 4

atrial pressure little bump

Question 5

Pressure in lymh?

Answer 5

low

Question 6

How are the root hairs of halophytes able 2 absorb water by osmosis from soil of salt marsh(2)

Answer 6

• LOWER WP inside root HAIR cells
• actively transport salts into root HAIR cells

Question 7

A DNA molecule has 2 polynucleotide chains- explain how they’re held 2gether (4)

Answer 7

• phosphodiester bonds in backbone
• hydrogen bonding btwn bases
• purine 2 pyramidine
• 2 bonds btwn AT, 3 btwn CG

Question 8

If populations of a species facing extinction are small and scattered, why is this a problem?

Answer 8

• hard 2 find a mate
• inbreeding= less genetic diversity
• more vulnerable to diseases/predators/poachers

Question 9

Captive breeding programs unsuccessful,what else could be done?

Answer 9

education/promote conservation projects

Question 10

-ve of erythrocytes not having a nucleus

Answer 10

• can’t do mitosis, no protein synthesis 4 repair, only anaerobic respiration

Question 11

Why don’t erythrocytes use the oxygen they carry (3)

Answer 11

• oxygen bound 2 haemoglobin
• lack mitochondria
• so no aerobic respiration

Question 12

With reference 2 blood vessel strcuture, why isn’t oxygen released till blood recahes capillaries?

Answer 12

-arteries have thick walls
- no diffusion thru artery walls

Question 13

name given 2 change in oxygen dissociation cyrve due 2 increasing CO2 conc?

Answer 13

Bohr effect

Question 14

Why does blood off-load more oxygen 2 actively respiring tissues than 2 resting tissue?

Answer 14

• actively repiring tissues have high pCO2
• lowred affinity of haemoglobin for oxygen
• dissociation of acrbonic acid leading to release of oxygen
• more oxygen released at same pCO2

Question 15

How does mass flow of phloem sap happen in plants with a vascular system? (5)

Answer 15

• assimilates in sieve tube
• enter sieve tube at source and lowers water potential in sieve tube
• water enters sieve tube by osmosis and increases hydrostatic pressure
• assimilates leave sieve tube by osmosis and lowers hydrostatic pressure
• assimilates move from high 2 low hydrostatic pressure

Question 17

Role of oncotic and hydrostatic pressure in tissue fluid

Answer 17

Hydrostatic pressure pushes plasma out of capillaries to form tissue fluid, while oncotic pressure pulls water back into capillaries due to plasma proteins remaining in the blood.

Question 18

What tye of enzyme breaks starch?

Answer 18

Carbohydrase

Question 19

Define the following types of immunity:

A) Natural active
B) Natural passive
C) Artificial active
D) Artificial passive

Answer 19

Natural active – Immunity gained from recovering after an infection
Natural passive – Antibodies transferred from mother to baby through placenta or breast milk
Artificial active – Immunity developed after vaccination
Artificial passive – Immunity from injection of ready-made antibodies

Question 20

define an inhibitor

Answer 20

a molecule that binds 2 an enzyme, changing the shape of the active site, preventing and esc froming

Question 21

Define a cofactor

Answer 21

A metal ion that attaches to the enzyme, changing the shape of the active site, increasing the likelihood of reaction

Question 22

Why are onion root tips used 2 observe cells undergoing mitosis? (2)

Answer 22

• root tip is the site of cell division
• Root tip is meristematic tissue
• no chlorophyll present so view of mitosis isn’t obscured

Question 23

Why do mammals store glycogen instead of glucose? (3)

Answer 23

• glycogen has many terminal glucoes molecules 4 quick hydrolysis when required
• insoluble therefore wouldn’t affect wp
• compact therefore can be stored in small space

Question 24

Describe how a molecule is prepared and secreted by cells of the salivary gland after translation has taken place (3)

Answer 24

• transport vesicle from RER
• modification/processing/folding
• at golgi
• packaged in2 secretory vesicles
• vesicles move along cytoskeleton
• vesicles fuse w/cell surface membrane
• secretion occurs by exocytosis

Question 25

How does the fluid mosaic model describe the structure of plasma membranes? (2)

Answer 25

- phospholipid bilayer - hydrophilic phosphate heads facing outwards - hydrophobic phosphate heads facing inwards - Proteins are free to move around - proteins scattered randomly through the phospholipid bilayer

Question 26

Why can progesterone move across membranes?

Answer 26

- non-polar/fat soluble molecule - SO diffuses thru phospholipid bilayer

Question 27

3 molecules ATP is made of?

Answer 27

- phosphate groups - adenine NOT ADENOSINE - ribose

Question 28

In 1990, carl woeses suggested a new top level taxon to the current classification system of living organisms, which he termed a domain. He used his results from studying RNA to organise organisms into 3 distinct groups a) name the cell component that appears in organisms of all 3 domains that woese suggested

Answer 28

Ribosomes

Question 29

2 defining characteristics of the domain Eukarya

Answer 29

nucleus DNA with , histones / (associated) proteins linear DNA (named) membrane bound organelles 80s ribosomes

Question 30

DNA ligase is one enzyme involved in the replication of DNA. Suggest 2 other enzymes involved and describe their functions

Answer 30

DNA helicase, unzips DNA molecule DNA polymerase, forms phosphodiester bonds Gyrase, uncoils DNA

Question 31

In 1958, Matthew Meselson and Franklin Stahl carried out an experiment that provided evidence to support the hypothesis of semi-conservative replication of DNA. Meselson and Stahl grew E. coli bacteria in a growth medium that contained only the heavy isotope of nitrogen 15N. They transferred the bacteria to a growth medium that had the light 14N isotope and allowed the bacteria to undergo cell division. After each division, the DNA from some of the bacteria was extracted from the culture and centrifuged to separate it. Fig. 25 shows the bands of DNA in the centrifuge tubes after a specific number of divisions. The tube labelled Generation 0 in Fig. 25 shows a single band of DNA containing bases that contain only the heavy isotope of nitrogen 15N. Explain how the results from the other generations provide evidence to support the hypothesis that DNA replication is semi-conservative

Answer 31

- tube with generation 1 shows (new) DNA / band , contains , light nitrogen / N14, and , heavy nitrogen / N15  - tube with generation 2 (new) DNA / band , made from only , light nitrogen / N14 - so a , light / N14 , strand of DNA must be a , template / parent strand , for the new molecule - tube with generation 10 (highest band gets thicker because more of the DNA is made from only , light nitrogen / N14

Question 32

The protease enzyme bromelain can be extracted from pineapples. A student investigated the effect of changing the concentration of the enzyme and measured the time taken to break down the protein gelatine. (a) State three variables that the student would need to control in order to make the results of this investigation valid.

Answer 32

1 temperature  2 pH  3 concentration of , protein / gelatine  4 volume / mass / surface area , of , protein / gelatine  5 volume of , protease / bromelain / enzyme  6 same source of , enzyme / gelatine  7 same reaction end point 

Question 33

How is rate of reaction calculated?

Answer 33

1/time

Question 34

What does SD show?

Answer 34

spread of data around mean, little variation=high repeatability

Question 35

What bond holds alpha glucose and fructose 2gether?

Answer 35

1,6 glycosidic bond

Question 36

Which is more soluble: amylose or amylopectin?

Answer 36

amylose

Question 37

Carbon dioxide release during respiration can affect the % oxygen saturation of haemoglobin. The tertiary structure of haemoglobin is affected when carbon dioxide reacts with water to form carbonic acid. This reaction releases hydrogen ions. Which of the statements, A to D, explains this change? A The release of hydrogen ions causes the pH to rise, which reduces haemoglobin’s affinity for oxygen. B The release of hydrogen ions causes the pH to rise, which increases haemoglobin’s affinity for oxygen. C The release of hydrogen ions causes the pH to fall, which increases haemoglobin’s affinity for oxygen. D The release of hydrogen ions causes the pH to fall, which reduces haemoglobin’s affinity for oxygen.

Answer 37

D