random

Question 1

explain the function of lysosomes in cells

Answer 1

lysosomes contain enzymes to break down pathogens
using hydrolytic enzymes
and can break down old organelles`

Question 2

explain why different antibodies need to be produced to give immunity to new strains

Answer 2

antibodies are specific to antigens so the variable region to the antibody is complementary to antigen

Question 3

explain how vaccination programmes can help to contril the spread of infecctions deasieases

Answer 3

aims to vaccinate the whole population
to develop long term immunity
vaccine allows most people to have an immune response to the antigen

Question 4

how does the oxygenator carry out functions of gas exchange?

Answer 4

oxygen moves into the blood and carbon dioxide moves from the blood by diffusion and there is a short diffusion pathway

Question 5

difference of structure of tunica media of muscular artery and aorta in terms of function

Answer 5

tunica media of aorta has more elastic fibres and this allows the aorta to stretch during ventricular contraction

Question 6

explain how the structure of collagen fibre provide skin with strenghth

Answer 6

covalant bonds between collagen molecules
covalent bonds are strong
overlapping molecules

Question 7

suggest why it is important to plants that water has a high latent heat of voporisation

Answer 7

plant leaves heat up and this leads to cooling effect

Question 8

why is it important for the control of the cardiac cycle that there is a shrt delay at the AVN after impulses have been sent out by SAN

Answer 8

atria and venticals do not contract at the same time and this allows the atria to empty compleatly

Question 9

explain how the blood pressure changes

Answer 9

1)opening of the tricuspid valve: pressure in right ventrical becomes lower than right atrium
2)opening of pulmonary(semilunar) valve: pressure in right ventrical becomes higher than pressure in pulmonary artery
3)help flow of blood: to prevent backflow

Question 10

what is meant by polysaccirides

Answer 10

large number of monosaccharides

Question 11

features of nonself antigens

Answer 11

stimulate immune response
usually glycoproteins
recognized by phagocytes

Question 12

list all the structures through which a blood clot in the left atrium must travel to reach the blood vessels supplying the brain

Answer 12

atrioventricular valve-
left ventrical
semilunar valve
aorta

Question 13

explain why blocking a small artery in the brain leads to brain damage

Answer 13

lack of oxygen

Question 14

explain how the primary transcript is modifyed to form mRNA

Answer 14

removal of introns

Question 14

why is it necessary for cholride ions to enter the red blood cell as hydrocarbonate ions leave

Answer 14

it replaces the negative ion

Question 15

explain how specialised cells in the gas exchange syestem prevent harmful microscopic particles from reaching the alvoli

Answer 15

production of mucus by goblet cells
mucus is sticky and traps the dust particles
the cilia waft the mucus away

Question 16

describe how the process of translation results in the formation of a polypeptide

Answer 16

-two codons at a time are exposed to the large subunit
-each tRNA brings a specific amino acid
-a tRNA anticodon binds to the mRNA codon
-complementary base pairing occurs through hydrogen bonds
-second tRNA brings another amino acid(next to the first one)
-peptide bond formation between the two amino acids

Question 17

difference. between scanning electron micrograph and transmission electron micrograph

Answer 17

SEM- shows 3d veiws
TEM-showing 2D

Question 18

why glucose molecules need to be cotransported with Na+ when it enters the cell through the membrane protein

Answer 18

glucose is moving agaisnt a concentration gradient
movement poward by inward movement of Na+

Question 19

explain how microvilli increase the uptake of glucose into an intestinal epithelial cell

Answer 19

increase in surface area so more transport

Question 20

suggest and explain the importance of mitosis by stem cells in the small intestine

Answer 20

-to replace old cells to allow tissues to function
-produce cells that are gentically identical and develop during infancy
-restore number of stem cells so there is constant supply

Question 21

outline the standard treatment that can be used for suspected cholera cases

Answer 21

-oral rehydration
-solution of water and salts like sodium

Question 22

suggest and explain why this treatment can help to prevent a larger outbreak of cholera

Answer 22

decreases recovery time
reduces diarrhoea production

Question 23

state 2 differences between sucrose and fructose, other than the number of carbon,hydrogen and oxygen atoms present

Answer 23

-sucrose is diassachrides
and a non reducing suger

Question 24

why is bird heart big

Answer 24

need more oxygen for physical activities such as wing muscles

Question 25

similarities and differences between introns and the exons of genes coding

Answer 25

similarities -both are transcribed differences -exons are coding sequences -exons join to form mRNA

Question 26

describe globular proteins

Answer 26

-3d -soluble in water(hydrophobic R-R group interactions) -included in metabolic reactions -

Question 27

describe fibrous proteins

Answer 27

-do not curl up -lie side by side to form fibres -not water soluble -not genrally phsiologically active -mostly play structural roles

Question 28

two different circulations of double circulatory syestem

Answer 28

pulmonary circulation systemic circulation

Question 29

main vein returning deoxygenated blood to the heart

Answer 29

vena cava

Question 30

type of blood vessel that connects capillaries and veins

Answer 30

venules

Question 31

carbonic acid forms?

Answer 31

hydrogen ions

Question 32

suggest how viruses can be of different shapes

Answer 32

the presence of phospholipid bilayer ensures flexibility

Question 33

one similarity and difference in virus and bacteria

Answer 33

similarity: both have DNA difference; bacteria has looped DNA

Question 34

in mitotic cell cycle if it stops at G1, what will happen?

Answer 34

-no S phase -no DNA replication -cell does not increase in size -failed to reach checkpoints

Question 35

why are there two types of drugs produced for an illness rather than 1

Answer 35

-if there is resistance to once, then the other one will kill -less likely for mutations to occur

Question 36

what is gene mutation

Answer 36

altered nucleotides in DNA

Question 37

explain why respiratory bronchioles do not have goblet cells

Answer 37

presence of mucus can hinder airflow to alveoli bc the lumens of airways are narrow and close to alveoli

Question 38

difference in epitheilium of alvoli and bronchai

Answer 38

bronchioles have columnar cells bronchioles are ciliated alvoli have squamous

Question 39

functions of smooth muscles

Answer 39

allow for contraction and changes diameter

Question 40

what will happen to Vmax and Km with non competative inhibatator

Answer 40

Vmax; decreases Km; stays the same

Question 41

actions of b-lymphocytes

Answer 41

1-pathogens invade 2-antigen presentation cell formation 3-only specific B lymphocytes has receptors with the complementary shape to antigen will be activated (clonal selection) 4-B cells will divide through mitosis (clonal expansion) 5-activated Bcells divide into plasma cells and memory cells (thelper cells release cytokines that allow blymphocytes to diffrenciate into plasma and memory cell)

Question 42

state what is meant by gene

Answer 42

i a sequence of nucleotides that forms a part of DNA molecule

Question 43

explain why blood taken from a person with an infectious disease may have a different number of white blood cells compared to blood taken from a healthy person

Answer 43

more white boood celss because 1-result of immune response 2-clonal expansion 3-increased production of phagocytes

Question 44

explain why sickle cell anemia is a disease

Answer 44

absence of good health produces symptoms like weakness

Question 45

S phase

Answer 45

dna replication -produces two genetically identical Dna molecule, one for each daughter cell

Question 46

metaphase

Answer 46

chromosomes align at equator -chromosomes oreintated so that sister chromatids will be shared out to daughter cellsna

Question 47

anaphase

Answer 47

centromere splits- that daughter chromasomes move to opposite poles

Question 48

suggest why daughter cells are not identical immediatly after cytokineses

Answer 48

unequal sharing of organelles