random Flashcards
explain the function of lysosomes in cells
lysosomes contain enzymes to break down pathogens
using hydrolytic enzymes
and can break down old organelles`
explain why different antibodies need to be produced to give immunity to new strains
antibodies are specific to antigens so the variable region to the antibody is complementary to antigen
explain how vaccination programmes can help to contril the spread of infecctions deasieases
aims to vaccinate the whole population
to develop long term immunity
vaccine allows most people to have an immune response to the antigen
how does the oxygenator carry out functions of gas exchange?
oxygen moves into the blood and carbon dioxide moves from the blood by diffusion and there is a short diffusion pathway
difference of structure of tunica media of muscular artery and aorta in terms of function
tunica media of aorta has more elastic fibres and this allows the aorta to stretch during ventricular contraction
explain how the structure of collagen fibre provide skin with strenghth
covalant bonds between collagen molecules
covalent bonds are strong
overlapping molecules
suggest why it is important to plants that water has a high latent heat of voporisation
plant leaves heat up and this leads to cooling effect
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
atria and venticals do not contract at the same time and this allows the atria to empty compleatly
explain how the blood pressure changes
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
what is meant by polysaccirides
large number of monosaccharides
features of nonself antigens
stimulate immune response
usually glycoproteins
recognized by phagocytes
list all the structures through which a blood clot in the left atrium must travel to reach the blood vessels supplying the brain
atrioventricular valve-
left ventrical
semilunar valve
aorta
explain why blocking a small artery in the brain leads to brain damage
lack of oxygen
explain how the primary transcript is modifyed to form mRNA
removal of introns
why is it necessary for cholride ions to enter the red blood cell as hydrocarbonate ions leave
it replaces the negative ion
explain how specialised cells in the gas exchange syestem prevent harmful microscopic particles from reaching the alvoli
production of mucus by goblet cells
mucus is sticky and traps the dust particles
the cilia waft the mucus away
describe how the process of translation results in the formation of a polypeptide
-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
difference. between scanning electron micrograph and transmission electron micrograph
SEM- shows 3d veiws
TEM-showing 2D
why glucose molecules need to be cotransported with Na+ when it enters the cell through the membrane protein
glucose is moving agaisnt a concentration gradient
movement poward by inward movement of Na+
explain how microvilli increase the uptake of glucose into an intestinal epithelial cell
increase in surface area so more transport
suggest and explain the importance of mitosis by stem cells in the small intestine
-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
outline the standard treatment that can be used for suspected cholera cases
-oral rehydration
-solution of water and salts like sodium
suggest and explain why this treatment can help to prevent a larger outbreak of cholera
decreases recovery time
reduces diarrhoea production
state 2 differences between sucrose and fructose, other than the number of carbon,hydrogen and oxygen atoms present
-sucrose is diassachrides
and a non reducing suger
why is bird heart big
need more oxygen for physical activities such as wing muscles
similarities and differences between introns and the exons of genes coding
similarities
-both are transcribed
differences
-exons are coding sequences
-exons join to form mRNA
describe globular proteins
-3d
-soluble in water(hydrophobic R-R group interactions)
-included in metabolic reactions
-
describe fibrous proteins
-do not curl up
-lie side by side to form fibres
-not water soluble
-not genrally phsiologically active
-mostly play structural roles
two different circulations of double circulatory syestem
pulmonary circulation
systemic circulation
main vein returning deoxygenated blood to the heart
vena cava
type of blood vessel that connects capillaries and veins
venules
carbonic acid forms?
hydrogen ions
suggest how viruses can be of different shapes
the presence of phospholipid bilayer ensures flexibility
one similarity and difference in virus and bacteria
similarity: both have DNA
difference; bacteria has looped DNA
in mitotic cell cycle if it stops at G1, what will happen?
-no S phase
-no DNA replication
-cell does not increase in size
-failed to reach checkpoints
why are there two types of drugs produced for an illness rather than 1
-if there is resistance to once, then the other one will kill
-less likely for mutations to occur
what is gene mutation
altered nucleotides in DNA
explain why respiratory bronchioles do not have goblet cells
presence of mucus can hinder airflow to alveoli bc the lumens of airways are narrow and close to alveoli
difference in epitheilium of alvoli and bronchai
bronchioles have columnar cells
bronchioles are ciliated
alvoli have squamous
functions of smooth muscles
allow for contraction and changes diameter
what will happen to Vmax and Km with non competative inhibatator
Vmax; decreases
Km; stays the same
actions of b-lymphocytes
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)
state what is meant by gene
i a sequence of nucleotides that forms a part of DNA molecule
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
more white boood celss because
1-result of immune response
2-clonal expansion
3-increased production of phagocytes
explain why sickle cell anemia is a disease
absence of good health
produces symptoms like weakness
S phase
dna replication
-produces two genetically identical Dna molecule, one for each daughter cell
metaphase
chromosomes align at equator
-chromosomes oreintated so that sister chromatids will be shared out to daughter cellsna
anaphase
centromere splits- that daughter chromasomes move to opposite poles
suggest why daughter cells are not identical immediatly after cytokineses
unequal sharing of organelles
