Stuff from the cool biology booklet Flashcards
How do you calculate magnification?
Picture size = actual size x magnification
What should you always talk about when asked about mitochondria?
respiration, energy release, 02 and glucose
Model answer for diffusion questions
what is moving?
how? (eg diffusion)
where does it move from? why?
from high->low conc
where does it move to, why?
what does it move across? (partially permeable cell membrane)
passive process
model answer for osmosis questions
water is moving via osmosis
where does it move from? why? what water potential there?
from high->low conc
where does it move to, why? water potential?
what does it move across? (partially permeable cell membrane)
until equilibrium reached
passive process
what happens when plant cells lose water?
they become plasmolysed
The tissue becomes flaccid
what happens when animal cells lose water?
shrink, become crenated
what happens when animal cells gain water?
swell, burst, undergo lysis
what must you mention when talking about active transport?
mitochondria
use up glucose/o2
to carry out aerobic respiration
atp formed/energy released
used by carrier proteins
to movr particles against conc gradient
what types of transport are used in the roots?
ions/minerals use active transport
water moves by osmosis
what three things do you always mention when talking about exchange surfaces’ adaptions
maximise SA, minimise diffusion distance, mantain steep conc gradient
what are the adaptions of the lungs in terms of exchange surfaces?
alveoli are spherical - SA
many alveoli
alveoli walls one cell thick
ventilate lungs by breathing - keep 02 levels in lungs high
blood removes 02 on other side of exchange surface, keeps conc low
what are the adaptions of the guts in terms of exchange surfaces?
many villi/microvilli
capillaries have one cell thick walls
capillaries close to exchange surface
intestinal living one cell thick
blood removes nutrients on other side to keep conc low
what are the adaptions of plant leaves in terms of exchange surfaces?
many air spaces
thin leaves
02 made by photosynthesis and diffuses out, co2 diffused in as it is used up
what is differentiation?
change in structure of a cell to become better suited to a role
what is specialisation?
when a cell is adapted to carry out a particular role
what are stem cells?
undifferentiated, unspecialised cells that can become any cell type, except adult stem cells- become a limited range of cells
what type of cells are formed from mitosis / meiosis
mitosis forms diploid clones, meiosis forms 4 different gametes
where is the duodenum?
SI
where is amylase made?
salivary gland, pancreas, duodenum lining
where is protease made?
stomach (pepsin), pancreas, duodenum lining
where is lipase made?
pancreas, duodenum lining
where does amylase act?
mouth, duodenum
where does protease act?
stomach, duodenum
where does lipase act?
duodenum
what is the product of amylase, protease and lipase respectively?
simple sugars (maltose)
amino acids
glycerol and fatty acids
What are the functions of bile?
Emulsify fats to increase SA
neutralise acidity of food from stomach
provide optimum PH for intestine enzymes
function of HCL in stomach
provide optimum PH for pepsin
sterilises+kill pathogens on food
what words must you mention when talking about enzymes?
active site
complementary shape
enzyme substrate complex
specific
substrate
products
lock and key
how does pH affect enzymes?
wrong pH, enzymes denature
active site changes shape
no longer complementary to substrate
fewer enzyme substrate complexes
reaction slows down or stop
how does temp affect enzymes?
increased->enzymes +substrate move faster
until optimum temp is reached (quote data!)
after optimum temp enzymes start to denature
active site changes shape, no longer complementary
fewer enzyme substrate complexes made
reaction slows or stops
what is metabolic rate?
the rate of chemical reactions in cells
How does a heart attack occur?
coronary artery blocked
blood flow restricted
glucose and oxygen not transported to heart muscle
less aerobic respiration
less energy released
less muscle contraction
which walls of the heart are larger and why?
left walls, more powerful muscle contraction needed as blood has to be pumped further (all the way around the body) on the left side
how is lactic acid broken down?
using oxygen
what do you need to mention when talking about O2 debt?
lactic acid formed by anaerobic respiration broken down using o2 into co2 and h20 to release energy
what is translocation?
the movement of dissolved sugars from the leaves to the rest of the plant
are viruses cells?
no
what are risk factors?
factors that increase the likelihood that you’ll get ill/harmed
what are the three ways that WBCs defend the body?
engulf pathogens
make antibodies
make antitoxins
ways to prevent infection spread
use good hygeine
isolate/quarantine the infected
kill / control vectors
vaccinate as many as possible
model answer for q about antibiotic resistance
-mutation
-causes variation in resistance to antibodies
-offspring inherit mutation
-population more resistant over time -non resistant bacteria wiped out
two main reasons antibiotic resistance is increasing
people don’t finish antibiotic courses
overuse of antibiotics
answer for a question on why we can’t cure colds/flus/viral diseases
viruses mutate
immune system can’t recognise new strain/antigens
no antibodies made to destroy them
model answer for vaccine/immunisation q
vaccine contains weakened/inactive pathogen
WBC regonise antigens in vaccine
WBCs release antibodies
WBCs become memory cells
if you get the “real” infection memory cells recognise antigens
quickly respond by producing antibodies which destroy pathogen before you get ill
when answering q about growing microbes, consider…
favourable conditions for microbe growth (warmth, 02, water, nutrients)
preventing contamination (state what needs sterilising/how to sterilise it)
health and safety (lids on petri dishes, not incubating above 25 degrees, hand washing,facemasks..)
what are the two types of culture medium?
agar jelly - solid- in petri dish
nutrient broth- liquid- in flask/container
what do cigarettes contain, what harm do they cause?
tar- causes cancer
CO- breathlessness, low growth rate in foetuses
nicotine- mostly harmless BUT addictive
obesity is caused by…
consuming more calories than you use
what can obesity lead to?
type 2 diabetes
arthiritis
heart disease
high blood pressue
alcohol causes
liver cancer and cirrhosis
brain damage
foetal alcohol syndrome
method for describing photosynthesis graphs
divide graph into chunks
tackle each at a time, using the descriptive phrase: “As [x axis] increases, [y axis] increases/decreases/stays constant up until [quote data point]” (i presume then explain why)
QUOTE DATA
during the day co2 levels are low because… (OPPOSITE TRUE FOR O2)
photosynthesis takes in co2
+occurs quicker than respiration
during nighttime co2 levels are high bc… (OPPOSITE TRUE FOR O2)
photosynthesis cant occur bc lack of light, so plants not taking up co2
aerobic respiration releasing co2
for qs on tropisms, what do you need to mention
which part is responding? (roots/shoots/stem)
how it responds? (up or down)
what respond to? (gravity/light/water)
how responds(auxin-distributed unevenly-unequal growth rate- causes bending)
what are different kinds of stimuli ?
light
chemicals (taste+smell)
pressure
temperature
sound
DON’T SAY: the frying pan is the stimulus. the temperature/heat is the stimulus
different kinds of receptors
light receptors in eye
chemical receptors in nose/tongue
pressure receptors in skin
temp receptors in skin
sound receptors in ear
When asked about a response arc, what do you need to refer to?
stimulus?
receptors?
sensory neurone, electrical impulse…
CNS and relay neurone
synapses and chemical signals
motor neurone
effectors?
response?
what can the effector be?
muscles for movement,
glands for secreting chemicals
model answer for blood sugar control?
pancreas (makes insulinnn????)
detects sugar levels
if high release insulin
insulin stimulates liver to take up glucose, convert to glycogen
if low, release glucagon
glucagon stimulates liver to break down glycogen into glucose and release into blood
which type of diabetes can you be born with?
1
what does FSH do?
matures eggs
stimulates ovaries to make oestrogen
what does oestrogen do?
stimulates lining of uterus to regrow
inhibits FSH production
stimulates LH release
what does LH do?
stimulates mature egg release from ovary (ovulation)
for homeostasis temperature control questions…
blood vessels (not capillaries) near skin surface constrict/dilate heat loss prevented/encouraged
hairs erect/flatten- insulation
sweating stops/starts - evaporation
shivering generates heat
model answer for shivering questions
muscle contraction
uses energy
aerobic respiration
uses 02 and glucose
generates heat (all other cold responses prevent it being lost)
three functions of kidney
maintain water and salt balances
excretion
what is excretion?
getting rid of metabolic (cell reaction) waste ie. urea, made in liver, and c02, produced by all cells during respiration, which is exhaled
what is egestion?
not excretion, getting rid of undigested food waste- faeces
what can co2 build up cause?
forms carbonic acid which denatures enzymes so has to be removed
how does salt build up happen and what does it cause?
water moves by osmosis
into cells with low water potential due to high salt conc
from cells with higher water potential
raises blood pressure and leads to heart problems
where are urea and urine made?
urea in the liver, urine in the kidneys
how do kidneys work?
filter plasma out of blood into kidney
large proteins +cells stay in blood, (too big to filter)
SELECTIVELY REABSORB all sugars,AAs,some water and salts by diffusion, then AT back to blood
excrete urea, excess h20+ salts as urine
why is urea more concentrated in the urine than blood?
after filtering, water is reabsorbed
urea not reabsorbed
flow chart of excess proteins to urine
excess proteins digested to AAs
deamination in liver to NH3
converted to urea
filtration in kidneys to urine
flow chart of how water controlled?
water levels in blood low
detected by pituitary gland
releases ADH
causes kidneys to absorb more water
making concentrated low volume urine
how does dialysis work?
pump blood through dialyser tube
dialysing fluid has same amount of glucose, nutrients, water, ions as normal blood- any excess diffuses out of blood into the fluid down conc gradient
no urea in dialysing fluid, so urea diffuses out of blood into fluid down conc gradient
bubble trap removes air bubbles
anticoagulant stops clotting in the machine
what is an allele?
different versions of the same gene, which codes for one protein each
how do you comment on genetic diagrams?
parent phenotype=
parent genotype=
gamete genotype=
punnet square cross
offspring genotypes and phenotypes (list all genotypes with phenotypes next to them)
what is a chromosome?
a structure that carries genes in the nucleus
why do gametes have half the number of chromosomes?
so they can have the correct amount when they fuse
for ethics qs on gene technology, you should cover…
benefits
economics/costs
effect on environment
religious opposition and morality/ethics
health and safety
what are plasmids used for gm
transfer DNA to microorganisms
if you are trying to gm engineer an animal/plant you…
… insert the DNA directly into them when they’re still an embryo
selective breeding model answer
select organisms with desired traits
only breed those organisms
select their best offspring and only breed those
repeat process over many generations
why do plants have big leaves?
increase SA
capture more light energy
for photosynthesis
+ successfully compete with other plants for light
reasons darwin’s theory wasn’t accepted at the time
religious opposition
not enough evidence
couldn’t prove how characteristics were inhgerited; they didn’t know about genes
how do plants prevent water loss?
curl/lose leaves- low SA
fewer stomata
less water lost
thick waterproof waxy cuticle
to pick up more water plants can
deep roots
more spread out roots
for questions about pyramids getting narrower at the top…
energy is lost
from each trophic level
do to movement, uneaten parts, excretion and heat lost
NEVER SAY ENERGY IS LOST THROUGH GROWTH
abiotic factors:
temp
light (for plants only)
water
food/nutrients
space/territory
pollution
biotic factors
competition
predators
disease
if you are asked to estimate a population’s size
divide study area into grid
select random coords
place quadrat down at coords
count num. of organisms or % cover within quadrat
(do the thing. we did with the sunflowers)
if you asked how a species changes over an area
lay measuring tape down-a transect
place quadrat down against transect at regular intervals
vegetarianism is better because:
fewer trophic levels
less energy lost
state how energy is lost [respiration,heat loss,uneaten parts, etc ]
