easter bio eoy corrections to learn

blood smear slide prep

blood @ one end of slide, smear across slide @ angle

interphase cell appearance

single dark area, individual chromosomes not visible

any microgragh question

mention magnification

RER --> secretion for protein

synthesised on ribosomes of RER, pass into lumen/cisternae of RER where folded or carbohydrate added, packaged into transport vesicles, transport vesicles move protein to Golgi apparatus where is modified and packaged into secretory vesicle

cytoskeleton function

• holds organelles in place

• aids transport of (named) molecules/organelles, cell movement

• maintains cell shape/structure/stability

ribosomes

found in both plant and animal cells

prokaryotic DNA

circular extrachromosomal, NOT linear

organelle movement within cell

attach to cytoskeleton, moved by protein motors

nile blue

used to stain nuclei (of living cells)

magnification - electron microscope

TEM higher than SEM

yeast

divide via budding, contain a nucleus and ribosomes, cell well made of chitin

bacteria

cell wall made of peptidoglycan

differential staining

distinguishing features, providing contrast

molecular formula of lactose

C12H22O11

glycogen structure

highly branched for quick energy release, broken down faster than starch due to many branched ends

polymers

sometimes composed of several monomers that are similar in structure but not identical

glucose properties

polar, soluble (due to OH groups allowing for H bonding), small - able to cross membranes

effect of temp on membrane permeability

@ low temp. pigment escapes through gaps between moving phospholipids, as temp increases, KE increases, more phospholipid movement, membrane becomes more permeable, more pigment loss - @ higher temp = greater membrane disruption, bilayer melts, membrane leaks, large increase in pigment loss

enzyme in formation of haemoglobonic acid

carbonic anhydrase

elements found in amino acids

C, H, O, N

collagen properties

insoluble, high tensile strength, resistant to stretching, flexible

bonding in protein levels

primary - peptide, secondary - hydrogen, tertiary - hydrogen, ionic, covalent (disulphide bridges), quaternary - hydrogen, ionic, covalent (disulphide bridges) dependent on R group

globular protein feature - spherical, no fibres

any question with water freezing/melting

ice expands, less dense than water (may cause membrane breakage)

water properties

solubility, polarity (due to dipole) - hydrogen bonding, lower liquid density

fat vs carb energy

fats have more C-C/C-H bonds, containing more energy per molecule, more energy in less space

monosaccharides

soluble, reducing sugars

genetic mutation effects

cause change in DNA base sequence, frameshift

DNA extraction

salt - breaks H bonds between DNA and water so DNA is less soluble, enzyme must be protease - to break down histone proteins, ice cold ethanol - temp reduces enzyme activity

DNA polymerase - catalyses formation of phosphodiester bonds

base structure

purines (A/G) - two rings, pyrimidines (C/U/T) - one ring, C---G, A--T/A--U

catalase

needs to break down H2O2 as it is toxic (triggers apoptosis), forming H2O and O2 - high turnover rate regulated by isolating catalase in peroxisomes, and releasing in small quantities so cells can limit the expression of catalase and enzyme concentration and therefore reaction, cells have no control over temperature or substrate conc so enzyme conc. is the only method of control

evaluating conclusion from graph/data

sample size, statistical test? error bars overlapping?

effect of hydrogen peroxide on plasma membrane

reacts with fatty acids/phospholipids/cholesterol, denatures transport proteins, membrane becomes more permeable

rate calculations

draw tangent from curve

induced fit

stronger binding between enzyme/substrate, placing substrate bonds under strain, decreasing activation energy

reducing number of transfers

decreases random error, improving accuracy, decreasing uncertainty/percentage error

cofactor

any non-protein substance required for an enzyme to catalyse

coenzyme

temporarily bound during reaction then leaves

prosthetic group

permanently bound, could be an organic molecule, metal ion or both

example

Cl- ions for amylase activity - causes conformational change that increases starch affinity, increases starch --> maltose catalysis

role of cell surface membrane

separate cytoplasm from tissue fluid, control transport of substances, site of chemical reaction, cell signalling

erythrocyte differentiation

develop large number of ribosomes in early stages, form lots of haemoglobin, digests organelles used for protein synthesis

embryonic stem cell research

test efficacy/toxicity of medicinal drugs, studied in development into different cell types, cell function studied under effect of certain diseases

muscle tissue

group of cells that contract together

muscle

organ consisting of muscle/connective tissues, nerve cells, blood vessels

independent assortment (metaphase 1+2)

round 1 - chromosomes, round 2 - chromatids

crossing over (prophase 1)

chromatids have new combinations of alleles, degree of variation depends on distance between chiasma of homologous pairs

cell cycle

during mitosis the nucleus divides, immediately followed by cytokinesis. interphase has 3 stages - DNA replication occurs during the synthesis phase, with check points G1 and G2 checking for cell size and DNA damage, and S checkpoint putting cell in apoptosis if it does not pass

mitosis prophase andmeiosis phrophase 2 differences

only one chromosome from each homologous pair involved in crossing over, chromosomes are recombinant (not genetically identical)

stem cells

can differentiate into specialised cells

genetic variation

independent assortment, crossing over, mutations

palisade cell adaptations

chloroplasts for photosynthesis, rectangular shape - closely packed into continuous later, thin cell wall - increased CO2 diffusion, greater light penetration

safe use of spirometer for extended periods of exercise

increase O2 conc. in chamber, meaning higher blood conc. of O2 maintained

flight and ventilation in insects

muscle contraction before or during flight increases ventilation of the tracheal system

only occurs during forced expiration

internal intercostal muscles contract

bronchiole smooth muscle

contracts to constrict/relaxes to dilate

sucrose entering sieve tubes from companion cells

decreases osmotic potential of sieve element sap

Casparian strip

suberin

apoplast vs symplast

majority via apoplast (between cell walls in intracellular spaces), only symplast (through plasmodesmata) can cross Casparian strip @ endodermis therefore plant regulates transport into vascular tissue

xerophyte adaptations

thick waxy cuticle, reduced number of leaves, reduced number of stomata, rolling/curling of leaves in dry conditions, small leaves, hairs, stomata in pits/depressions, succulence (stores water in stems - ribbed or fluted so can expand when more water is available), stomata close during the day

hydrophyte adaptations

floating plants contain aerenchyma tissue (contains many air filled lacunae - bouyancy for floating leaves, resevior of oxygen for respiration, increased diffusion of gases into roots), stomata only present in upper epidermis to minimise gas exchange with atmosphere (permanently open, guard cells inactive) waxy cuticle - repels water from leaf surface

marram grass habitat

sand dunes, dry - sand is free draining, salty spray from sea, windy - increases transpiration, blown sand may bury or sandblast

marram grass adaptations

thick waxy cuticle (protects from sand abrasion), rolled leaves when water in short supply, hairs trap moisture, dense spony mesophyll - fewer air spaces, extensive root system

prickly pear cactus adaptations

spines instead of leaves (reduces SA for transpiration, deters grazing animals), thick waxy cuticle, succulent, open stomata in day, and closes at night (water potential gradients smallest), classulacean acid metabolism - absorbs CO2 at night and stores as an organic acid until next day when can photosynthesise, dessication tolerance, extensive root system

haemoglobin in oxygen transport

partial pressure is the driving variable - loads in the lungs (high pO2), unloads at tissues (low pO2), cooperative binding - each O2 binding causes conformational change, making loading and unloading progressively easier, sigmoid-shaped curve - slow initial loading, steep middle, plateau at saturation

Bohr effect

CO2 --> H2O+CO2-->H+ + HCO3- (catalysed by carbonic anhydrase)

H+binds to haemoglobin --> decreases affinity for O2 --> curve shifts right

chloride shift

HCO3- leaves RBC into plasma, Cl- enters to maintain electrochemical balance

dissociation curve shifted left

higher oxygen saturation, higher oxygen affinity, can pick up O2 at lower partial pressures

valves in veins

prevent backflow of deoxygenated blood due to low pressure, allows one way flow back to heart, arteriole structure and function

larger organisms need transport systems

more respiring cells, smaller SA:vol - diffusion pathway is too long, oxygen/nutrient transport

it is small 🙅‍♀️

large SA:vol

proton pump

actively transports H+ ions out of the cell, into the cell wall, creating a concentration gradient

sucrose transport

against concentration gradient

cotransport

secondary active transport

source and sinkn in winter/early spring

source - roots/tuber/storage organs because leaves are not yet developed

sink - growing parts, leaf buds, flower buds meristem

substances that can diffuse through the phospholipid bilayer

small, non-polar, hydrophobic

fluid mosaic model

fluid: phospholipids/embedded proteins can move around relative to each other (within the monolayer)

• membrane proteins can diffuse to different areas as needed

• membrane-bound organelles can fuse together, vesicles can form/fuse with cell membrane in endo/exocytosis

mosaic: resembles mosaic from above

lower phospholipid density

more membrane proteins (receptor/secretory function)

microscopes mag/res

light: x2000, 200nm

SEM: x200 000, 3-10nm

TEM: x500 000, 0.5nm

erythropoiesis

• specialises for oxygen carrying

• rapidly synthesising lots of haemoglobin

• removes protein synthesis organelles (named)

• biconcave shape to maximise SA:vol (increasing oxygen absorption)

respiration questions

• aerobic/anaerobic?

• impact on/location of energy release

stem cells in medicine

• undifferentiated cells able to specialise into almost any cell (depends on toti/pluri/multipotency)

• divide unlimited times

• healthy cells replace unhealthy cells

transplants

• cell membrane from donor tissue (patient’s own) contains non-self markers 

• identification as pathogen + rejection

• immune response against stem cells

template vs coding strand

antiparallel complementary strands joined by hydrogen bonds, forming a double helix

designing experiment

• control experiment

• control variable

• repeats

• calcs (rate/mean)

• statistical test

join letters to options (not mcq)

can repeat options!!!

unless says otherwise

mitochondrial structure

• surrounded by double membrane, inner membrane folded to form cristae

• matrix formed by cristae contain enzymes for aerobic respiration, producing ATP

cellulose

• insoluble

• high tensile strength (due to H bonding between parallel chains)

• flexible

• unreactive