Bio paper 1

Question 1

parts of the brain

Answer 1

cerebrum - intelligence, personality, consciousness

cerebellum - balance, coordination of movement

medulla - unconscious activity like heart rate and breathing

hypothalamus - homeostasis

Question 2

sensory neurone structure

Answer 2

cell body in the middle
myelin sheath
axon - away from cell body
dendron - to cell body
dendrites receiving with receptor cells to axon terminals then synapses

Question 3

motor neurone structure

Answer 3

dendrites to massive cell body then axon with myelin sheath to axon terminal
gaps between myelin sheath are nodes of ranvier

Question 4

relay neurone structure

Answer 4

dendrites small cell body with axon no myelin sheath to axon terminal

Question 5

to see close or far

Answer 5

close:
ciliary muscles contract, suspensory ligaments relax

far: js the opposite

Question 6

repeatable meaning

Answer 6

repeat the exact same experiment with same people and if you get same results it’s repeatable

Question 7

reproducible meaning

Answer 7

same results but different experiment/technique/people doing it

Question 8

plant hormones

Answer 8

auxin - control growth, promote cell elongation

gibberelins - breaks seed dormancy, promotes germination

ethene - ripens fruit

Question 9

killing weeds use

Answer 9

auxins
selective herbicide
kills broad leaved plants not narrow leaved
makes weed grow too fast
uncontrolled growth kills plant

Question 10

promoting root growth use

Answer 10

auxin
produce identical plants from cuttings
cut off shoot put rooting powder and plant
roots grow anchor in soil and take up water and minerals

Question 11

delaying ripening use

Answer 11

auxin
delay ripening
allow harvest to be collected at same time
prevent fruit dropping off trees early

Question 12

ripening fruit use

Answer 12

ethene
fruits ripen quicker
ready earlier in growing season

Question 13

producing seedless fruit use

Answer 13

auxin
seeds produced after plant is pollinated
auxins applied to unpollinated flowers
produces seedless fruit

Question 14

controlling dormancy use

Answer 14

gibberellins/auxins
seeds remain dormant until ideal growth conditions
prevents germinating at end of summer so they survive winter
commercial growers trigger seeds to germinate in winter

Question 15

parthenocarpic meaning

Answer 15

seedless fruit

Question 16

factors that affect transpiration

Answer 16

light intensity - stomata open in light, more light intensity, more water evaporates, rate increases until all stomata open
(graph is up until plateaus)

temperature - increase temp, water evaporates quicker, diffusion becomes more rapid, increases rate
(graph is straight up)

air movement - air moves over surface, moves evaporated water away, faster air moves, faster water moved away, increases conc gradient, so increases rate
(graph is curved up then slightly plateaus)

humidity - humidity is amount of water in air, higher humidity, more water, decrease humidity, increase conc gradient, increase rate
(graph goes straight down)

Question 17

random vs systematic error

Answer 17

random - affect results in unpredictable ways and fluctuate around the true value

systematic - consistently affect the results in the same direction

Question 18

reliable meaning

Answer 18

how close the repeated measurements are to each other

Question 19

phloem vs xylem

Answer 19

xylem - water, one way, continuous tube, dead, lignin lined

phloem - sugars, two way, sieve plates, alive, cellulose lined

Question 19

food parts and their tests

Answer 19

lipids - 3 fatty acids and a glycerol, ethanol, clear to milky white
starches - glucose, iodine, orange to black
sugars - benedicts, blue to red
proteins - amino acids, biurets, blue to purple

Question 20

stains for microscopy

Answer 20

methylene blue - animal cell nuclei
iodine - plant cell nuclei
crystal violent - bacterial cell walls

Question 21

to see in dim or bright light

Answer 21

dim light:

radial muscles contract (outer ones)
circular muscles relax (inner ones)

bright light is js opposite

Question 22

homeostasis defintion

Answer 22

keeping conditions in body stable

Question 23

metabolism meaning

Answer 23

the rate at which all chemical reactions in the body occur at

Question 24

backflow of blood symptoms

Answer 24

legs swell, pain, itchy skin, numbness, cramps, blood clots, varicose veins

Question 25

explain how a mutation causes a different protein to be produced

Answer 25

The order of bases in DNA code for the production of a protein, so a different order of bases means a different protein would be produced. In transcription, DNA is used as a template to produce mRNA, therefore a change in the bases in DNA will cause a change in the bases in mRNA. In translation, the order of the bases in mRNA determines the order of the amino acids joined together. This is because different tRNA molecules will bind to the mRNA, making a new protein. (adapt to your question)

Question 26

if not enough oxygen, not enough haemoglobin, blood not circulating enough etc, symptoms

Answer 26

breathlessness, light headed, headaches stitches, muscle cramps blue or pale skin anemia irregular heartbeats, palpitations tiredness, fatigue, lethargy

Question 27

cell cycle

Answer 27

cell growth, DNA replication, cell growth, movement of chromosomes G1 - growth S - DNA synthesis/replication G2 - growth and preparation for cell division M - movement of chromosomes - mitosis G1, S and G2 are all the interphase, mitosis is the process of everything splitting so prophase - chromosmes pair up metaphase - line up on equator anaphase - spindle fibres pull them apart telophase - nuclear membrane forms cytokinesis - cytoplasm splits

Question 28

why something is misleading

Answer 28

sample size is small showed an improvement not cure one one form tested could get worse again don't know if it's permanent

Question 29

what scientists need to do before releasing to general public

Answer 29

test more people see if it has side effects see if it lasts long term determine the cost

Question 30

cellular respiration meaning

Answer 30

Respiration which occurs in all cells, where glucose is broken down to release energy, in the form of ATP

Question 31

describe how the triplet code determines the structure of the protein

Answer 31

Each codon codes for one amino acid. The order of the codons determines the sequence of amino acids. The sequence of amino acids determines which protein is made.

Question 32

why do scientists think menstrual blood stem cells are better than embryo stem cells?

Answer 32

quick to culture easily obtainable frequently accessible source less ethical issues less invasive techniques

Question 33

explain how guard cells change to open stomata

Answer 33

Guard cells photosynthesise, so in brighter light, they can use the energy of the sun to photosynthesise more, creating sugars. Because the water potential is lower inside the cell, water enters the guard cells via osmosis. The guard cells swell and become turgid. The thickened inner part of the wall bends less than the outer part, resulting in the guard cells curving and forming the stomatal opening.

Question 34

why does plotting range bars on a graph improve interpretations made from it

Answer 34

identifies uncertainty in results shows overlap of data shows how consistent the data is shows how precise a measurement is

Question 35

why is homeostasis important for metabolism in humans?

Answer 35

homeostasis allows metabolic reactions to proceed at appropriate rates by maintaining optimum conditions for enzymes

Question 36

when using a colour scale some problems that might occur and how to improve it

Answer 36

the colour of the food might affect the colour of the solution people may see colours differently someone might be colourblind colours may be mistaken is doesn't give numerical/exact/accurate values use a range of known concentrations of solution and compare colour with a colour chart or use a colorimeter

Question 37

units of measurement

Answer 37

kilometre - 1000 metres metre - 1 metre cm - 0.1 metres millimetres - 10 to the -3 micrometres - 10 to the -6 nanometres - 10 to the -9 picometres - 10 to the -12 femtometres - 10 to the -15

Question 38

emphysema causes some walls in alveoli to break down resulting in a smaller number of larger air sacs explain the effect of emphysema on oxygen diffusiing into the blood

Answer 38

it reduces the total SA of alveoli so reduces the SA:V ratio of alveoli so diffusion of oxygen reduced

Question 39

phenols are chemicals that inhibit enzymes, they bind to amino acids on enzyme molecules how do phenols inhibit enzymes

Answer 39

the phenols alter the shape of the active site/block the active site so the substrate no longer fits/binds with the active site

Question 40

why has our understanding increased

Answer 40

tech has developed improved accuracy of measurements

Question 41

what are barriers to scientists understanding more?

Answer 41

difficulties in getting individuals for case studies people are reluctant to give consent may cause harm to patients interpreting data from case studies is very complex ethical issues with experimenting on animals

Question 42

why do scientists peer review

Answer 42

to inform other scientists to see if scientists can replicate the work to have it peer-reviewed to get recognition for their work to check their results

Question 43

role of DNA template and mRNA nucleotides in protein production

Answer 43

used for trancription DNA is used to make mRNA

Question 44

role of tRNA nucleotides and ribosomes in protein production

Answer 44

used for translation mRNA attaches to ribosome tRNA reads the triplets on the mRNA

Question 45

pros and cons of DNA database

Answer 45

pros: to check on heredity look for genetic disorders identify health risk factors idea of choosing correct medication to confirm a person's identify cons: people wanna avoid being identified for a crime people wanna avoid high insurance costs reluctance of employers to offer jobs remain unaware of family history people dislike sharing personal details

Question 46

brain scans

Answer 46

CT scans - uses x rays, shows structure only, good for seeing tumours or brain injuries, lower reso than MRI MRI - uses magnetic fields and radio waves, shows detailed soft tissue, good for seeing brain abnormalties, more expensive than CT electrical stimulation - uses electrodes often during brain surgery to understand which area of the brain controls what

Question 47

anaerobic respiration

Answer 47

animals: glucose -> lactic acid plants: glucose -> ethanol + carbon dioxide C6H12O6 -> 2C2H5OH + 2CO2

Question 48

photosynthesis stages

Answer 48

stage 1: light dependent energy transferred splits water into oxygen gas and hydrogen ions stage 2: light independent carbon dioxide gas combines with hydrogen ions to make glucose

Question 49

heart

Answer 49

from right to left: vena cava - triscuspid valve pulmonary artery - pulmonic valve aorta - aortic valve pulmonary vein - biscuspid valve deoxgenated blood goes vena cava, right atrium, right ventricle, pulmonary artery, lungs, get oxygenated blood to go in pulmonary vein, left atrium, left ventricle, aorta, rest of body

Question 50

endocrine system

Answer 50

renal artery brings blood from liver (makes urea) goes into afferent arteriole glomerulus ultrafiltrated filtrates go into bowman's capsule blood goes into efferent arteriole and become the capillaries surrounded the loop of henle filtrates go into pct (proximal convoluted tubule), selective reabsorption of glucose and mineral ions then into loop of henle, salt levels are regulated then into dct (distal convoluted tubule) then into collecting duct, water levels regulated rest of filtrates go out of kidneys down the ureters to bladder, out urethra and into toilet as urine blood goes back into the renal vein and rest of body glomerulus and bowman's capsule are in kidney cortex, loop of henle and collecting duct in kidney medulla kidney surrounded by capsule

Question 51

factors affecting diffusion and why

Answer 51

conc gradient - increase it, increase speed of diffusion distance - reduce it, increase speed temp - increase, increases speed of particles, so increases diffusion surface area - increase it, increase speed because more space to diffuse into

Question 52

plant and animal cells in different concentrations

Answer 52

plants: dilute - turgid normal - flaccid concentrated - plasmolysed animals: dilute - lysis normal - normal concentrated - crenation

Question 53

plant structure

Answer 53

waxy cuticle upper epidermis - clear allows light to pass through palisade mesophyll - carrys out photosynthesis spongy mesophyll - gas exchange vascular bundle in spongy mesophyll lower epidermis with guard cells and stomata - essentially water balance waxy cuticle

Question 54

transpiration stream

Answer 54

root hair cells take in water and dissolved minerals from soil, first passively so diffusion and osmosis, then active transport water and minerals move from cell to cell through the root until they reach the xylem vessels water and minerals move up through the xylem vessels to the stem and leaves water moved into the leaves and evaporates from the leaf cells through the stomata as water vapour the loss of water in the leaves reduces he presseure in the xylem vessels water moves up through the tube going from high pressure to low pressure (osmotic pull)