questions ive got wrong Flashcards
in nucleotides, what components contain carbon
- pentose sugar
- nitrogen containing bases
what is the role of cholesterol
-binds to phospholipids fatty acid tails, increasing packing of membrane thus reducing the fluidity of the membrane.
why do single celled organisms not need a specialised surface for gaseous exchange
- its a single cell ( has a large sa to vol ratio)
- it has a short diffusion pathway- easy for gasses to diffuse in and out
describe the structure of the plasma membrane
-primarily made of phospholipid bilayer that contains proteins. hydropho9bic tails face inwards and hydrophilic heads face outwards. cholesterol bound to fatty acid tails. Extrinsic and intrinsic proteins present. Glycoproteins stick out the bilayer.
why are different enzymes involved in different processes
enzymes are SPECIFIC and the substrates have diff shapes. the active site and a substrate have to be complimentary to form ESC.
what forms enzyme product complex
destabilizing of bonds
what improves reliability
-repeating experiment
explain the induced fit hypothesis
- active site changes shape so a closer fit occurs (more bonds form between active site and and substrate)
- forms ESC
- destabilising of bonds forms EPC
- activation energy reduced
- active site changes again when product leaves
what is the detailed structure of cells visible with only an electron microscope
ultrastructure
what do xylem vessels contain
lignin
2 types of cells found in phloem tissue
-companion cells and sieve tube elements
how to see amino acids in chromatography
spray with ninhydrin
what are the coils of amylose and amylopectin held by?
hydrogen bonds
difference in amino acid structure in fibrous and globular
fibrous- repetitive amino acid sequence
globular- varied in amino acids- hydrophilic and hydrophobic
what can stem cells be used for
- asexual reproduction
- growth of organism
- repair of damaged tissues
whats the point of lignin
- to waterproof the cell which improves adhesion of water
- strengthens the cell to prevent collapse of xylem
- ( for some)spiral pattern allows for flexibility
whats the function of bordered pits
allow water to move between xylem vessels, lateral flow and allow for supply of water through the plant and to other cells
state 3 roles of membranes inside cells
- cell compartmentalisation
- provide selective permeability
- site of attachment for enzymes
whats the term organ
more than 1 type of tissue working with many tissues to perform a specific function
what side does the bhor shift cause the sigmoid to move
to the right
what allows for the movement of cillia
what structure allows for secretion of mucus
- cytoskeleton
- centriole
how is hydrostatic pressure generated in the heart
by the contraction of ventricles
explain why the hydrostatic pressure drops as u move away from the heart
as you move away, there are more smaller vessels, the vessels have a larger total lumen. Arteries can also stretch and expand and at the capillaries, there is loss of fluid.
describe how the action of the heart is initiated and coordinated
-SAN initiates impulse which is excitation across the atrial walls causing the atria to contract (atrial systole). The impulse is then received at the AVN, delayed then conveyed down the bundle of His into the purkinje fibres which reach along the apex of the heart causing the ventricle to contract bottom upwards
whats a source
source= where sucrose and assimilates are loaded into the phloem
whats a sink
sink= where sucrose and assimilates are unloaded from the phloem
What thing do plants need if they have a low sa to vol ratio
a transport system
what pressure does transpiration produce
negative pressure
whats the function of the bordered pits
to allow water to move between vessels, can bypass blockage
-also supplies water to other tissues/cells
what do plasmodesmata allow for
flow of substances between cytoplasm of diff cells
whats transpiration
the evaporation of water from the leaves of a plant
whats the role of elastic fibers during ventilation
- to prevent bursting
- to allow for recoil
- returns air sac to its original shape and size to help expel air
how does refreshing of air in the air sacs maintain a diffusion gradient
it increases partial pressure of oxygen in the air sacs so conc is higher than that in the blood. It decreases partial pressure of CO2 in the air sac so conc of CO2 in the air sac is lower than that in the blood
in terms of binomial name, what does the 1st part tell us
the genus
in terms of binomial name, what does the 2nd part tell us
the species
how does histamine stimulate smooth muscle contraction
-histamine binds to a receptor on the plasma membrane of a muscle cell which produces a response
Another action of histamine is to make capillary walls more permeable.
Suggest two effects this increased permeability may have on the surrounding tissues
- more tissue fluid is formed
- oedema occurs
- more white blood cells can pass into tissues
- larger molecules pass into the tissue fluid.
tell the difference between the domain system and the 5 kingdom system
- for the domain system, bacteria and archaea are split into two groups because they are different.
- the domain system is based on differences in DNA
- domain groups eukaryotes together
give an example of a selection pressure
- a certain environment due to predators, prey/food ability
give 2 pieces of evidence that can be used to identify organisms as belonging to two diff species
- different cytochrome C
- different genes
how is it possible to confirm that two organisms are different species
-interbreed them and if they are able to produce fertile offspring, they are the same species, but if its infertile, they are different species
whats continuous evolution and whats discontinuous evolution
- continuous is the effect of many genes and may be due to the effect of the environment
- discontinuous is the effect of 1 or few genes, it has little/no environmental effect
two characteristics of birds share with members of the animal kingdom
- cells have no cell wall
- multicellular
domain that a parrot belongs to
-eukaryote
whats Variation
differences in species
whats the name of the process where new species arise
speciation
the system of classifying organisms according to their observable features or genetic characteristics is called
taxonomy
whats its called whne organisms are classified into large groups then divided into smaller groups
hierarchy
what is the term used to describe the evolutionary relationships between organisms
phylogeny
give an example of gaining accurate results in an experiment
using more intermediate results
give an example of gaining reliable results in an experiment
repeat the experiment again
outline the process of budding in yeast
nucleus divides- cell bulges, nucleus moves into bulge- this gets pinched off
describe the function of glycoproteins in the cell surface membrane
- act as antigens
- recognition of cells
- receptor/ binding site for proteins
- cell adhesion to hold cells together.
- attach to water molecules to stabilise membrane
what’s the function of an intrinsic protein/ protein
allow communication across membrane OR allow, polar /
charged, particles to pass through membrane
what is meant by the term cell signalling
communicating between cells to trigger a response.
-cells work together
explain how a glycoprotein can act as a receptor
it has a specific shape, its complimentary to shape of trigger- trigger attaches to receptor
how do polar substances enter a cell
through, pore / channel, proteins ;
(using), transport / carrier, proteins- facilitated diff or active transport
what’s the cofactor for amylase
Cl-
whats the prosthetic group for carbonic anhydrase
Zn2+
brief description of inhalation
ribcage moves downwards and outwards: external intercostal muscles contract- diaphragm contracts
talk about the pressure in:
- blood in aorta
- tissue fluid
- lymph
- blood in vena cava
-blood in aorta high -tissue fluid low -lymph low -blood in vena cava low
why is it bad that endangered populations are scattered and isolated from each other
- as isolated, there may not be substantial numbers to breed so fertile offspring cant be produced.
inbreeding also may occur so small gene pool- could all be wiped out by the same disease- also more vulnerable to poachers and predators
how can zoos contribute to the conservation of endangered species
-by giving education and awareness to people
why do viruses not replicate in red blood cells
- as erythrocytes dont contain RER for protein synthesis and the virus is unable to replicate on its own
why does plasmodium enter RBCS
uses it to hide from the immune system
why do erythrocytes not make use of the oxygen they are transporting
oxygen is bound to haemoglobin- they lack mitochondria so no aerobic respiration and dont need ATP to move as they have mass flow
explain why the blood offloads more oxygen to actively respiring tissues than to resting ones
- active tissues have a high amount of co2 present.
- high co2 results in lowered affinity for haemoglobin for oxygen. co2 results in dissociation of carbonic acid/ increase of H+ leading to the releasing of oxygen.
explain how mass flow occurs
- sucrose and assimilates are in the sieve tube elements.
- assimilates enter the sieve tube at source and lowers the water potential.
- water enters the sieve tube by osmosis and increases hydrostatic pressure
- assimilates then leave the sink increasing water potential.
- water then leaves the sieve tube by osmosis and lowers hydrostatic pressure
- assimilates move from a high to low hydrostatic pressure down a concentration grad
describe how the stomata is adapted to its role
- unevenly thickened cell wall
- able to change shape/ bend
- transport proteins in pm
- mitochondria to provide atp
use the cohesion tension theory to describe how water moves from roots to leaves
evaporation at the top of a plant creates tension in the xylem, water molecules stick together/ are cohesive and the chain is pulled up by tension
what 2 assimilates are loaded into the sieve tube element
sucrose and amino acids
what would u see in companion cells using an electron microscope
- many mitochondria
- plasmodesmata between companion cell and sieve tube
transpiration
the loss of water vapour from aerial parts of a plant
transpiration stream
movement of water (up xylem vessels) from roots to surrounding tissues
what happens to hydrostatic pressure in plant at a low temp
active trasnport requires atp,
at low temps, little kinetic energy thus less respiration/ atp so less loading sugars into sieve tube element, low hydrostatic pressure created
what does the release of hydrogen ions cause in rbcs
fall in pH, which reduces haemoglobins affinity for oxygen
elements in cholesterol
C, H , O
elements in insulin
C, H, O , N ,S
elements in ATP
C, H, O, N, P
1 Property of water making it an ideal habitat for animals
high specific heat capacity so can easily maintain temp
what can students do to ensure they have confidence in their results
- repeat experiment multiple times
- calculate the mean
- identify anomalies
why do large organisms need a circulatory system
-large organisms have a large sa to vol ratio, rate of diffusion= too slow and not sufficient enough for metabolic demands and sufficient removal of waste products
why does melting point decrease as saturation decreases
less saturated= more kinked (more c=c bonds) so less uniformly packed so lower temp needed
whats the bond between a pentose sugar and a phosphate called
a phosphodiester bond
two similarities and two differences between the DNA nucleotide (phosphate, deoxyribose, adenine )and ATP
similarities:
- both have a pentose sugar
-both contain adenine
-both contain a phosphodiester bond.
differences:
-ATP contains 3 phosphate groups instead of one
-deoxyribose in DNA nucleotide is replaced by ribose in ATP
how do hairs reduce transpiration rate
hairs trap water vapour so reduce water loss
what are tissues
a group of cells that are specialised and working together
what are homologous chromosomes
made up of:
- one maternal and one paternal copy
- carry the same genes
- carry different alleles
- have the same banding pattern
- are the same length
- centromere is in the same place
Name two parts of a plant where meristematic tissue can be found.
apex of root
apex of shoot
bud
State one way in which the products of meiosis are different from the products of nuclear
division in meristematic tissue.
meiosis= daughter cells are haploid
=the resulting cells are called gametes
=4 cells are produced
=the 4 cells are genetically different
describe the secondary structure of collagen
a left handed helix
a-glucose + a-glucose
maltose
what type of immunity is provided by vaccination
active artificial
how does viral RNA from a virus cause viral protein to be produced
the viral RNA acts as MRNA and carries the code for the viral protein to the ribosome
explain why a mutation in viral RNA leads to a change in 3-d shape of a protein antigen
- diff sequence of amino acids is made
- quaternary (3d) structure affected by change of amino acids as it alters ionic and hydrogen, hydrophilic and hydrophobic.
describe what t-killer does
cytotoxic, releases toxic substances to kill infected cells
