OCR A-Level Biology

Explain genetic drift

change in gene pools. allele frequencies changes No natural selection - it happens randomly. Extreme examples: Founder effect- most common in small populations. Bottleneck- when a population declines to a lower number.

what is the chloride shift and the Bohr shift

chloride shift is an input of cl- ions to maintain the charge in the cell as a BUFFER . Bohr shift-lower the affinity of oxygen so dissociated in respiring tissues with higher partial pressure of co2

chromatin

chrommatin-DNA and histone proteins nuclear envelpe is a double membrane

stages of mitosis explained

chromosomes condense, become visible nuclear envelope breaks down centrioles at the poles chromosome split at centromeres to poles nuclear envelope reforms , cytoplasm divides

what does cladistic mean what are nodes

clades are the relationships to a common ancestor nodes are areas of divergence in a genetic tree

diffences between plants and animals

cell walls , vacuole , chloroplast

Causes of kidney failure and treatment

heart diseases ,hypertension diabetes, melitus renal dialysis and kidney transplant

funtion of hepatic artery, portal vein and hepatic vein.

hepatic artery - supply o2 to active hepatocyes for liver function portal vein, deoxgenated blood ,dissolved nutrients for digestive system vein- from digestive system detoxified to heart

where does hepatic artery, vein ,portal vein go

hepatic artery- liver to heart(oxgenated) hepatic vein-from body to heart hepatic portal vein - from intestine has dissolved nutrients

What is Selective Reabsroption

high pressure forces water and solutes through the basement membrane and into the Bowman's capsule•This liquid is now known as the 'glomerular filtrate'What is left in the capillary?•Proteins•Blood cells•Molecules bigger than 69,000 RMM will remain in the blood.Selective reabsorption•As fluid moves along the nephron, substances are removed•Sodium-Potassium pumps move sodium ions from the cells lining the PCT into the tissue fluid•This reduced the concentration of sodium ions in the cytoplasm •Sodium ions are transported to cell, with glucose or amino acids, by facilitated diffusion•As gluc and amin acid conc rise , these substances diffuse out into the tissue fluid•Process may be enhanced by the active removal of glucose and amino acids•Tissue fluids substances diffuse into the blood and are carried away•Reabsorption of salts, glucose and amino acids reduced the water potential in cells and increases it in the tubule fluid•Water enter cells•

what is hypotonic,isotonic ,hypertonic

hypotonic-water enters,causes plasmolysis cell burst Isotonic-no net movement of water hypertonic-water leaves the cell (crenation)

Effect of CO2 concentration on photosynthesis

if carbon dioxide concentration was increased:○More carbon dioxide fixation allows for more GP, TP and ribulose bisphosphate to be created○Stomata will be open more, causing an increased loss of water and wilting○Stress response will close the stomata○This will reduce co2 supply○Photosynthesis rate will slow

What is the refractory period?

immediately after the cell becomes depolarised, it begins to repolarise•When sodium channels open, potassium ion channels open also•Potassium diffuses down the concentration gradient out of the cell •This outflux of positively charged ions makes the cell's charge become more negative•Eventually the potential difference (difference in charge across the cell membrane) overshoots○This is called hyperpolarisation•The original, resting potential (-60mV) is restored •Regions of the neuron that are in the refractory period cannot become re-charged •This ensures the action potential moves in a single direction

why is fetal hemoglobin curve shifted left of adult

in the sinusoidal curve fetal hemoglobin has higher affinity for oxygen from the mothers blood so oxygen absorbed from a lower partial pressure from low environment fetal hemoglobin has high affinity.

ABA function

inhibits seed germination• Causes stromal closure when plant is water stressed

efficient exchange system

lots of capillaries, high surface area to volume ratio good blood supply steep concentration gradient short diffusion pathway

what is the role of Henle

make filtrate concentrated and conserve water(water leaves descending limb)passive movement of water leaving, ions leave ascending limb by (active) hairpin counter-current multiplier

B lymphocytes (2 cells)

mature in bone marrow bind to apc clonal selection, clonal expansion PLASMA CELL produce antibody B MEMORY CELL

T lymphocytes ( what cells do they make)(4)

mature in thymus gland T memory cells-obvious t regulator cells- the clean up of chemicals after proliferation t killer cells- bind to pathogen and destroy. perforin T helper cells release cytokines to active b cells

Explain micropropagation

meristem removed put in agar plate callus is inserted (mass of undifferentiated cells) into agar with hormones , cytokines , glucose , amino acid , phsophate and auxin explant (transferred piece of tissue grown into plant)

What is high-throughput sequencing?

methods of rapid, inexpensive gene sequencing developed

functions of cytoskeleton

microtubles and micro filaments, transport molecules in cells mechanical strength and support movement of the cell anchoring the nucleus motor protein move vesicles on mircotubles

Assumptions of Hardy-Weinberg

random mating, no natural selection, no genetic drift, no gene flow, no mutation , large population

explain the function of selective reabsroption

reabsorbed glucose ,amino acids , ions from the filtrate , membrane has sodium potassium ion pumps and co-transporter for glucose(sodium)as well as microvili lots of mitochondria to supply ATP for active transport

Selective reabsorption

reabsorption of useful molecules, glucose, amino acids , ions using active transport co transporter of sodium ions carrier proteins

what is the function of kidney.

regulate , water volume, pH ,ion content, selectively re absorption in renal artery and veins,micro villi brush border has lots of mitochondria in digestive system

medulla oblongata function

regulating vital functions involuntarily (breathing Breathing movements○, digestion,Action of smooth muscle in the gut, heart rate)

What is a limiting factor?

An environmental factor that reduces the rate of a process

How does Acetylcholine esterase work

Enzyme in the synaptic cleft•Hydrolyses acetylcholine to ethanoic acid and choline•Stops transmission of signals •Ethanoic acid and choline are recycled•Re-enter synaptic knob by diffusion•Recombined to acetylcholine using ATP from respiration in the mitochondria•Stored in synaptic vessels for future use

What stain is used for cytoplasm

Eosin Pink

what stains do what eosin, orecein, methylene, sudan red, iodine

Eosin-(Cytoplasm) , acetic orecein (dna) , methylne blue (nucleas) sudan red(lipid) iodine(starch)

What stain is used to stain The nucleus

Methelene blue/ Toluidene Blue

The immune system 3 functions

Neutralization-binding to the antigens, prevent their function Opsonination- makes it easier for phagocyte to engulf Agglutination(a glue) sticks pathogens then they are engulfed by phagocytes

explain Nitrogen Fixation

Nitrogen Fixation• Nitrogen is incredibly unreactive when in the atmosphere• Plants need a supply to be 'fixed'• Nitrogen fixation can occur when:• Lightning strikes• Haber process• Nitrogen fixing bacteria (Rhizobium) fixes it• Bacteria has a mutualistic relationship with the plant providing in with nitrogen and receiving carbon compounds in return

Explain the Role of Water in the Light Dependent Stage

Photosystem 2 contain an enzyme that splits water into protons, electrons and oxygen•This is photolysis•Some of the oxygen is used in aerobic respiration•Water is a source of hydrogen ions, which are used in chemiosmosis•Protons are accepted by a coenzyme NADP, which is reduced to reduced NADP and used in the light independent stage

Epithelial cells of the Bowman's capsule structure How is glomerular filtrate formed

Podocytes-Finger like projections called major processes make gaps between cells Filtrate from blood can pass into the lumen of the Bowman's capsule• High pressure forces some water and solutes through the basement membrane and into the Bowman's capsule•This liquid is now known as the 'glomerular filtrate'

What are introns and exons?

Post-transcriptional gene regulation•Regions of DNA that don't code for genes are called introns they separate... •Regions of DNA that are expressed, called exons•Both are transcribed, but resulting mRNA is modified to remove the introns

what are Pacinian corpuscles and what is the structure

Pressure receptor in skin•Consists of concentric rings surrounding a nerve ending•Pressure causes the rings to apply pressure on the sensory nerve fibre•Nerve fibre detects change in pressure - not constantly applied pressure

definition of Ecosystem

dynamic system of interactions involving a community of living organisms and the abiotic factors of their environment

benifits of GM plants

effective use better yield /disease resistant good models for medicine easy to harvest mono culture

Explain oxidative phosphorylation

electron acceptors ,red Nad,fad hydrogen atoms split at matrix to electrons and protons ,protons are pumped across to intermembrane space from energy realesed by electron moving down electron channels (cytochrome) H+ conc high across membrane proton motive force, chemisomotic potential flow through ATP synthase , add pi to adp

difference between the endocrine and exocrine gland

endocrine. ductless glands, secrete hormones in blood streams, controls long term activity exocrine ,may or may not have a duct, travels in ducts, short term activity

other forms of Nitrogen fixation

free living and mutualistic bacteria (free living) and mutualsitc living in nodules of legumes by Rhizobium

What do transcription factors do?

proteins that control which genes to express or suppress , bind to promoter regions, can inhibit the attachment of RNA suppress, transcriptions(proto oncogene stimulate the start of mitosis)

what are the wavelenths of phtosystem 1 and 2

ps1(700nm) and ps2(680nm) light dependent ps1 and 2 cyclic photophrolation is only ps1 stroma to thylakoid lumen

explain Germ line therapy

putting healthy alleles into germ line cells or embryo , affecting unborn individual and future generations, we don't know how all the genes will interact.

electrophorisis

separation of the fragments based on size using an electric current(cut up with a restriction endonucelase) inside agarose gel plate medium, buffer solution to maintain ph moves from - to + DNA loading dye radioactive or fluorescent

Types of mutation

substitution, (insertion, deletion) cause frameshifts

types of gene mutation

substitution-least dangerous as dna code is degenerate insertion-one base added on the base pairs (frame shift) deletion one base deleted (frame shift)

What happens in the Krebs cycle

takes place in matrix,1. Acetyl group and oxaloacetate join forming Citrate (6C)2. Citrate is decarboxylated and dehydrogenated by NAD+.5C compound formed. Hydrogen pair accepted by NAD, reducing it 5C compound is then decarboxylated and dehydrogenated, forming 4C compound and another molecule of reduced NAD. 4C changed to another 4C compound, with ADP being phosphorylated to ATP7. FAD becomes reduced and removing another hydrogen pair8. 3rd 4C compound is further dehydrogenated, regenerating oxaloacetate

chemicals defense of plants

terpenoids-oils with antimicrobial properties phenols, interfere with digestion of insects Alkaloids- give bitter taste (nicotine, caffeine defensins-proteins that inhibit ion transport hydrolytic enzyme-between cells

Way genes can be manipulated (4)

DNA profiling Genomic sequencing Genetic engineering Gene therapy

What enzymes does the pancreas secrete? (3)

"Trypsinogen; lipase, amylase, etc."

How does Glucagon bring about its response

(glycogenolysis) Glycogen to be converted to glucose Production of glucose by conversion of amino acids and fats

what does the enzyme catalase do

(hydrogen peroxide)H202 catalyses breaks this down into hydrogen and water

what is a sacromere

(smallest contractile unit) the unit of repeating structural and function unit of skeletal muscle Span from one Z-line to the next•Z-lines closer together during contraction

how do you use a respirometer to investigate rate of respiration

1. Set up the apparatus as shown○Manometer contains liquid that moves as oxygen in tube A is used up 2. The germinating seeds release carbon dioxide 3. Carbon dioxide is absorbed by the sodium hydroxide○Therefore has no effect on volume of air inside tube A 4. Germinating seeds use up oxygen ○This decreases volume of air in the tube○Liquid in manometer is drawn up towards tube A 5. Rate of movement of liquid in manometer indicator of rate of respiration 6. Can change environmental conditions such as temperature, light intensity to observe how these factors affect rate of respiration

How do plants grow (2)

2 process in the meristem tissue○Cell elongation○ Cell division •Apical Meristems are located behind shoots and are responsible for shoots getting longer•Lateral bud meristems are found in buds and give rise to shoots•Lateral meristems are found near the outside of shoots and root and make them wider•2 cell walls are formed○

Net products of Glycolysis

2 x ATP•2 x NADH•2 x Pyruvate○2 molecules produced per glucose molecule○ (in the cytoplasm)

How is CO2 transported in the blood?

5% carried dissolved in plasma, 10-20% forms carbaminohaemoglobin, 75-85% converted in to carbonic acid them to hydrogen carbonate ions in rbc cytoplasm c02 combines with h20 via carbonic anhydrase

explain aseptic techniques

A a set of methods used to avoid introducing unwanted microorganisms into our culture• Aseptic technique means ensuring:• Hands always washed• Working area disinfected• Nearby Bunsen burner warms air and causes airborne microbial contaminants to rise away from work area(convection currents)• Place neck of any open test tubes/containers over the Bunsen burner to prevent bacteria in surrounding air from entering the vessel• Avoid removing petri dish lid entirely• Sterilise any equipment in the burner before making contact with the microorganism

What is a gene mutation and what are types of mutations (3)

A gene mutation is a permanent alteration in the DNA sequence that makes up a gene 1.Substitution a nucleotide base is replaced with another 2.Insertion an extra nucleotide base is inserted into the sequence causing 'frameshift' where all the subsequent bases are shifted down 1 place 3.Deletion the absence of a nucleotide, causing 'frameshift'

Bohr shift

A lowering of the affinity of hemoglobin for oxygen, caused by a drop in pH; facilitates the release of oxygen from hemoglobin in the vicinity of active tissues. H+ ions ascociate with hemoglobin , O2 unloaded at higher partial pressure

What is a photosynthetic pigment, what does it do.

A molecule that can absorb one or more specific wavelengths of light•Each pigment can absorb wavelength•Having primray and assessory maximizes energy absorption•These are arranged in photosystems(1&2)

What is negative feedback? (2)

A response to a change in the body that counteracts or opposes the initial change. eg thermoregulation and Blood sugar regulation

What is a synapse?

A synapse is a junction between two neurons. The space between the neurons is called the synaptic cleft and is about 20nm wide. An action potential travels from one neuron to the next via the synapse via substances called neurotransmitters such as acetylcholine (ACh)

what are the 4 blood groups

A, B, AB, O

What does ATP do in Muscular contraction

ATP provides the energy that allows binding, tilting and releasing on the myosin heads•It is the force that causes muscular contraction

What happens at the End of Nervous Stimulation & muscle relaxation

ATP pump actively pumps Ca ions from the sarcoplasm to the cisternae of the SER•Ca ion concentration falls below the threshold level•Troponin is released and is bound back to Ca•This causes the tropomyosin to go back to the myosin binding sites•The muscle relaxes

Detail Transmission Across the Synapse

Action potential arrives at synaptic knob•Voltage-gated ion channels open•Calcium ions diffuse into the synaptic knob•Calcium ions cause the synaptic vesicles to move to and fuse with the presynaptic membrane•Acetylcholine released by exocytosis•Acetylcholine diffuses across cleft•Acetylcholine binds to the receptor sites on the sodium ion channels in the postsynaptic membrane•Sodium channels open•Sodium ions diffuse across post synaptic membrane into postsynaptic neurone•Excitatory postsynaptic potential (EPSP) is created•EPSPs can combine, reaching the threshold potential•New action potential created in the postsynaptic neurone

Uses of ATP (4)

Active Transport, Bulk Transport (Endocytosis and Exocytosis), cell division, muscular contraction,protein synthesis

Ways to immobilise enzymes

Adsorption• Enzymes bound to e.g. clay surface by hydrophobic interactions and ionic links• Weak bonds — some enzymes break loose• Covalent bonding• Enzymes bound to e.g. clay surface by covalent bonds• Sharing electrons = strong bonds • Can be expensive and reduce enzyme action • But enzymes unlikely to break free into reaction mixture• Entrapment• Enzymes trapped in matrix• Enzymes fully active • Substrate diffuses into matrix• Product diffuses out of matrix • E.g. calcium alginate beads• Membrane barrier• Semi-permeable membrane around enzymes • Substrate small enough to pass through membrane to meet enzymes • Limits rate of reaction

Advantages and disadvantages of Ectotherms

Advantages Less food used in respiration○ Less food required○ Greater proportion of energy derived from food can be used for growth• disadvantages: ○Less active in cooler temperatures ○May not be capable of activity during cold winters

Advantage and disadvantages of Endotherms (2)

Advantages ○Constant body temperature regardless of external environment ○Activity possible in cooler temperatures○ Able to inhabit cooler parts of the world• Disadvantages:○lot of energy intake used to maintain body temperature ○More food required ○Less energy from food can be used for growth

explain genetic modification in plants

Agrobacturium tumifacien is used to insert a Ti plasmid into plant this recombinant DNA has a marker gene (diease resistant) callus are formed (mass of undifferentiated cells) explant/plantlet is grown in a growth medium

explain (3) Plant chemical defenses

Alkaloids○Make plants taste bitter to deter herbivores• Pheromones○Released from one plant and affect another• Tannins○Toxic to microorganisms/herbivores○Make the leaf taste unpleasant

role of synapses

Allows signals from different part of nervous system to create the same response○Useful when different stimuli are warning us of danger

Uses of ATP in the body (5)

Anabolic reactions (building large molecules) •Catabolic (breaking down molecules) •Active transport• Secretionof products Endocytosis• Replication of DNA Movement of organelles and of cells themselves• (cytoskelaton)

What are endotherms?

Animals who maintain body temperature through metabolic heat, independent of external temperature eg mammals and birds

What are ectotherms?

Animals whose body temperature is determined by their environment/ Behavioral changes lizards

What hormones does Alpha and beta cells secrete

Areas in the pancreas called the Islets of Langerhans contain 2 types of cells○Alpha cells and Beta cells•Alpha Cells Secrete glucagon•Beta cells Manufacture and secrete insulin

Process of water reabsorption

As the fluid moves down, the water potential falls○Water is lost to surrounding tissue fluid○Sodium and chloride ions diffuse into the tubule•As the fluid moves up the ascending limb, the water potential rises○At the base, sodium and chloride ions diffuse out○Sodium and chloride ions are actively transported out○Wall of the ascending limb is impermeable to water○Fluid loses salt, but not water, when moving up the ascending limb

Generation of nerve impulses (how)

At rest neurones have higher concentration of sodium outside the cell○Steep concentration gradient across cell membrane ○Cell charge is -60mV compared to extracellular environment•Sodium can move into the cell by gated channels○Causing cell to depolarise — become electrically charged•Gated channels stimulated to open by action of synapse•A few channels open — a few sodium ions move into the cell•The membrane depolarises○Becomes less negatively charged compared to the extracellular environment•If the threshold potential is reached (enough sodium ions enter the cell to surpass threshold), this initiates a positive feedback loop ○Threshold is -50mV•More sodium channels open•Cell becomes more depolarised

Pituitary Gland function

Attached at the base Endocrine gland Secrete a variety of hormones works with hypothalamus

what Enzyme is coded for by lac operon

B-galactosidase- Break down Lactose to Glucose ○Lactose permease- increase the uptake of lactose by e-coli

explain Denitrification

Bacteria can convert nitrates back to nitrogen gas When bacteria involved are growing under anaerobic conditions, they can produce nitrogen gas and nitrous oxide

what is biomass and trophic level

Biomass = combined total weight of a set of individual organisms Trophic Level = the level which an organism feeds in a food chain

what causes genetics variation in genes

Bivalent and crossing over of chiasmata (prophase 1) Independent assortment line up at equator randomly (meta 2) random mutations different gametes possibilities

How is water content of blood controlled

Brain releases antidiuretic hormone •ADH travels to the collecting duct the Cell have membrane bound receptors for ADH•ADH binds to receptors•Aquaporins sent in vesicles to the cell surface membrane•Aquaporins inserted into cell surface membrane•Walls of collecting duct more permeable to water•More water moves into the medulla by osmosis•Water potential of the blood rises back to the set level•Brain stops releasing ADH

difference between Cns and the PNS

CNS is brain and spinal cord, mainly unmylienated schwaan cell connects receptors to effectors PNS- rest of the neurons , mylienated bundle to make nerves have ganglion's

explain the organisation of nervous system

CNS(brain and spinal cord) /PNS all the receptors then Somatic /Autonomic from autonomic Sympathetic/Parasympathetic

Transcription factors

Can be proteins or noncoding pieces of RNA attach/detach from DNA to control which genes are expressed

How does adrenaline bring about an effect

Cannot enter target cell•Binds to target cell•Target cells is associated with adenylyl cyclase•Adrenaline is the first messenger molecule•First binds to specific receptor on cell surface membrane•Binding activates adenyl cyclase•This enzyme converts ATP to cyclic AMP (•cAMP is a secondary messenger molecule•)Causes an effect inside the cell via activating enzyme action

Explain the Calvin Cycle

Carbon dioxide from the air diffuses into the leaf○ into the chloroplast envelope○In the stroma, carbon dioxide combines with the 5C ribulose bisphosphate○Reaction is catalysed by the rubisco enzyme○Two 3C compounds, called glycerate phosphate (GP) are produced- Some GP is used to make amino acids and fatty acids○GP is reduced and photophosphorylated to another 3C compound, triose phosphate (TP)○ATP and reduced NADP are used in this reaction○5/6 TPs are recycled to ribulose bisphosphate- Pairs of TP combine to form hexose sugars

Explain Type 1 Diabetes Mellitus

Caused by auto-immune disease Body attacks its own beta cells Body cant manufacture sufficient insulin Cannot store excess glucose as glycogen

How does Auxin bring about a change.

Causes cell elongation○Increases stretchiness of cell wall by increasing hydrogen ions○ATPase enzyme moves more ions through the plasma membrane, into the cell wall○Low pH allows wall loosening enzymes to work○ break bonds in the cellulose, allowing cells to expand

What happens in the lag phase of the growth curve.

Cells increase in size• Enzymes synthesized• No cell division• Gives time to ensure a stable environment•(acclimatizing ) Population remains fairly constant

What are The mammalian nervous system subdivided into

Central Nervous System (CNS) Peripheral Nervous System (PNS)

Structure of the adrenal medulla and effects (3)

Centre of the gland Manufacture and release adrenaline/noradernaline○Effects include:- Relaxation of smooth muscle in the bronchioles- Increase volume of heart- Increase heart rate- Vasoconstriction- Dilation of pupils- Stimulate conversion of glycogen to glucose- Cause body hair to erect

Explain nitrification

Chemotrophic bacteria absorbs ammonium ions• Ammonium ions are released in putrefaction of proteins• Nitrosomonas bacteria oxidises ammonium to nitrates• Nitrobacteria oxidise nitrites to nitrates• As these reactions requires oxygen, it only occurs in well aerated soil

Explain the hair pin counter current multiplier

Close arrangement of the ascending and descending limb•Increases the efficiency of salt transfer from the ascending to descending limb•Salt concentrations build up in the surrounding tissue•Movement of salts into the medulla creates a low water potential•Removal of ions from the ascending limb means at the top, urine is dilute•Water is then reabsorbed, according to the needs of the body

describe the features of the batch culture

Closed environment• Competition for limited resources• Easy to set up and maintain• Less efficient as the fermenter is not in operation full time• Useful for producing secondary metabolites• Once culture is finished, product is removed and purified• Fermenter is sterilised before culture can begin again

what is the compensation point

Compensation point is the term used to refer the state in which a plant is when the rate of photosynthesis and the rate of respiration are equal. there is no net change in carbohydrate content because it is being generated at the same rate that it is being consumed.

What does the cerebellum do?

Controls balance, equilibrium, and muscle coordination. and muscle memory processes information from:○Balance organs of the inner ear

Hypothalmus function (2)

Controls most of the homeostatic mechanisms eg osmoregulation Controls the autonomic nervous system and endocrine glands via hormones

How to Place a gene inside a vector

Cut plasmid at specific site using restriction enzymes•Cuts made by restriction enzymes match the ends of the isolated gene○The complementary ends are called sticky ends•DNA ligase catalyses insertion of gene into plasmid •Gene can also be sealed in an attenuated virus

Explain Electrophoresis

DNA samples treated with restriction enzymes to cut them into fragments•DNA samples placed into wells of the(agarose) gel•Gel is immersed in a tank of buffer solution•Phosphate groups make DNA negatively charged, so DNA diffuses through the gel towards the positive electrode•Shorter lengths of DNA move faster than longer lengths, so move further•Position of fragments can be shown by a dye that stains DNA molecules(DNA negative cos of phosphates)

Pyrosequencing

DNA sequencing technology break DNA into fragments 300-800 base pairs separate the template strands immbolised the strand

Liver function and diagram (3)

Detoxification of Blood Storage of Glycogen Breakdown of Erythrocytes Production of plasma protein deamination of amino acids

Causes of Kidney Failure (4)

Diabetes mellitus Heart disease Hypertension Infection

What are endocrine glands?

Ductless Glands that release molecules directly into the blood•No duct involved

what is Somatic cell gene therapy

During growth, cells become specialized•In these specialised cell, genes are switched on and off•Although the cell has a full genome, not all of it is active○Adding Genes- Some diseases caused by faulty alleles- Engineering a functional copy of that gene into the cell means that the polypeptide can be produced- Functional gene product created○Killing Cells- Cancerous cells can be made to express certain genes and create proteins- These can make the cells vulnerable to attack by the immune system- Targeted cancer treatments

What are some Biotic factors

Effects of living components• Food supply• Predation• Disease

What are some abiotic factors?

Effects of non-living components pH• Temperature• Soil type sunlight water

Final stage of respiration

Electron transport chain (ETC)○Electron carriers are embedded in mitochondrial membrane○Co-enzymes NAD and FAD are reoxidised when they donate H atoms to these carriers○H atoms split into protons and electrons○Electrons move down the chain○They are finally donated to oxygen, the final electron acceptor•Chemiosmosis○As electrons flow, energy is released○This is used to pump protons into the matrix This builds up a proton gradient (and electrochemical gradient)○Potential energy builds up in the intermembrane space○Hydrogen ions are only able to diffuse through ATP synthase ○This drives the reaction of ADP and Pi, forming ATP•Oxidative Phosphorylation○As protons flow through ATP synthase, they drive rotation○This joins ADP and Pi, forming ATP○Electrons finally passed to oxygen, reducing oxygen to water

Why does CO2 need to be excreted?

Excess CO2 is toxic•High levels of carbon dioxide Reduce the oxygen carrying capacity of the red blood cells○Combines with haemoglobin to form carbaminohaemaglobin, which has a lower affinity for oxygen

What is Excretion and what is metabolic waste?

Excretion = the removal of metabolic waste products from the body. Metabolic waste = Unneeded byproducts produced as a result of normal metabolism. That need to be removed from the body as they can become toxic in large quantities eg co2 , urea

What happens in the log/exponential phase of the growth curve.

Exponential growth due to high metabolic activity and reproduction• Primary metabolites produced• Exponential growth (of no. of bacteria and product)

What is the basement membrane?

Fine mesh of collagen fibers and glycoproteins- Acts as a filter to prevent the passage of molecules with a RMM of over 69,000- Most proteins are held in the capillaries of the glomerulus

How do Primary and secondary messengers work

First messengers are hormones that do not enter target cells. This includes all non-steroid hormones. They exert their action by binding to signalling proteins on the cell surface membrane, which triggers a change inside the cell, usually carried out by a second messenger. cAMP is an exemplary second messenger. First messengers often trigger the action of a second messenger via a G protein, which is a protein that spans the cell surface membrane and enables communication between molecules outside the cell and molecules inside the cell.

what are Accessory pigments ,eg?

Found around PS•Absorb light from the sun and pass this onto the primary pigments○E.g. Carotenoids, Chlorophyll B xanthophill(500,640)

what are Accessory pigments ,eg?

Found aroung PS•Absorb light from the sun and pass this onto the primary pigments○E.g. Carotenoids, Chlorophyll B xanthophill(500,640)

Commercial use of Gibberlins (2)

Fruit Production○ Delays senescence○ Make fruit last longer on shop shelves

What is Germ line Therapy

Gene engineered into sperm or egg•Ensures all cells in the adult organism will have a copy of it•Illegal in humans

What are homeobox genes/what does it do

Genes that turn on/off development of specific body parts•DNA sequence that is found within many genes•They are grouped together as homeotic genes in a 'hox cluster'•These genes are involved in the regulation of anatomical development○Very important thus highly conserved •More complex organisms have more hox clusters •Homeobox genes expressed in specific patterns in certain stages of development•Activated and expressed from anterior to posterior•Very similar across species and highly conserved○Indication that they first arose in early common ancestor•Regulate development of embryos along anterior-posterior axis○Determine where limbs branch off

Explain the Gene sequencing

Genomes mapped to identify which part of the genome they have come from PCR to grow and amplify the gene sample As the cells grow in culture, many copies of the sections are produced•These are clone libraries•The cells containing the specific BACs are taken and cultured•DNA is extracted and cut up by restriction enzymes•Fragments separated using electrophoresis•Each fragment is sequenced using an automated process•Computer regions compare overlapping regions from the cuts made by different restriction enzymes

Outline oxidative phosphorylation

Glycolysis 2 net ATP , 2 red Nad in cytoplasm Link reaction(mitochondrial matrix) de carboyxlation, de hydrogentation + coenzyme A Krebs cycle - aceyl co enzyme A + oxaloactete(4c) to citrate(6c)happens twice + chemisosmosis

Sympathetic effect on the body (fight or flight)

Heart rate increases Much more blood and oxygen needed Saliva production inhibited Feeding not the main priority(gut process inhibited) Radial muscles contract Pupil dilates

Parasympathetic effect on the body (rest and digest)

Heart rate slowed, Less blood needed Saliva production stimulated,Food can be eaten Pupil constricts the retina

How do you let genes enter target cells

Heat shock○Bacteria subject to fluctuating temperatures between 0C and 42C ○Cell walls and cell membranes become more permeable ○Recombinant DNA enters cell more easily•Electroporation ○High voltage applied to cell and the membrane becomes more permeable •Transfection ○Gene inserted into bacteriophage which infects bacterial cell (viruses) liposome(vesicles carrying DNA)

What are Liver Cell called and what are Kupffer cells

Hepatocytes Specialised macrophages• in sinusoids•Break down and recycle old red blood cells•Haemoglobin is broken down into bilirubin○This is the brown pigment in faeces

advantages and disadvantages of adult cell cloning

High yield, saves rare and endangered animals, can be produced quickly lack of genetic diversity, animal welfare concern (beliguem blue), health issues , low success rate high costs

What is homeostasis?/ What factors are controlled (5)

Homeostasis is the regulation of internal environments with a certain range Temperature• Blood glucose concentration• Blood salt concentration •Water content• Blood pressure• Blood carbon dioxide partial pressure (blood pH)

What are Exocrine glands

Hormones Secrete molecules into a duct

Explain the sacromere structure

I Band○Thin actin filaments •Z line ○Region where actin myofilaments are anchored•A band ○Region containing the whole length of the myosin microfilament•M band○ Region where sarcomere connects to the skeleton•H band○

Explain automated DNA sequencing

If fluorescent markers are added to the chain, DNA polymerase is thrown off•The strand cannot have any more nucleotides•Process:○Primer anneals at the 3' end, allowing DNA polymerase to attach○DNA polymerase adds free nucleotides, so the strand grows○A modified nucleotide is added ○Enzyme is thrown off○Reaction stops○In every strand the final nucleotide has a specific colour○As these strands are run through a machine, a laser reads the colour sequence- Move in increasing size order- Sequence of colours and so bases can be displayed

How does light intensity affect the rate of photosynthesis?

If light intensity reduced:○Levels of ATP and NADP would fall, as the light dependent reaction cannot occur○Conversion of GP to TP requires ATP and reduced NADP, so this process will slow down○As ATP is used to convert TP to ribulose bisphosphate, levels of this will also fall○Reduction in ribulose bisphosphate means less carbon dioxide can react○Eventually the whole cycle stops

Temperature effect of photosynthesis

If temperature was raised:○Below 25 degrees activity in light dependent stages is minimally affected○Activity of molecules in the Calvin cycle are increased as they gain more kinetic energy○Higher temperatures will increase transpiration and cause the plant to wilt○Stress reaction will cause the stomata to close, reducing carbon dioxide availability○High temperatures may denature rubisco○At higher temperatures, rubisco is more likely to bind to oxygen than carbon dioxide○Photosynthesis rate will start to decrease

Smooth muscle properties

Involuntary contraction• Spindle shape cells contain bundles of actin, myosin and a single nucleus •Contracts and fatigues slowly •Involved in the movement of materials along a tube

What are the subdivisions of the PNS?

Involuntary part of the PNS•Can be further subdivided:○ Sympathetic- Prepares us for high activity- Fight or flight response Involves noradrenaline- Motor neurons are connected by ganglia Same signal can stimulate many motor neurons in different organs○ Parasympathetic- Relaxing responses Involves acetylcholine- Maintains a suitable state for non-threatening conditions

lac operon (structure and function)

Lac operon is a section of DNA within the bacterium DNA○Structural genes code for the enzymes○Operator region can switch the structural genes on and off○Promoter region is a length of DNA which the RNA polymerase can bind to begin the transcription of the genes•Regulator gene is not part of the operon and is some distance from it (codes for repressor proteins)

How does the Lac operon in the presence of lactose

Lactose binds to the other side of the repressor, changing its shape•Repressor can now not bind to the operator region•Repressor is now able to break away from the operator region•Promoter region is unblocked•RNA polymerase is now able to bind to this region•This system acts as a molecular switch•The enzymes can now be translated

Describe the Cerebrum

Largest part•Involved in 'higher' brain activities•Divided into 2 hemispheres○ •Outermost layer is highly folded

How does leaf loss occur?

Leaf senescence causes auxin production at apical bud to stop○Makes abscission zone more susceptible to ethene○Drop in auxin production causes an increase in ethane production○Increases production of the enzyme cellulose- Digests walls of cells in the abscission zone- Causes petiole to separate from stem

What is summation?

Low-level signals may be amplified•Persistent stimulus may cause several action potentials•May cause generator potentials to join together to produce an action potential

Adapations for selective reabosrption

Microvilli increase surface area• Membrane contains co-transporter proteins that transport glucose and amino acids with sodium ions in facilitated diffusion •Many mitochondria( for ATP generated)

Why does the e-coli express some genes

Most genes that code for functional enzymes are transcribed constantly. The lac operon is an example of a gene that is only transcribed in times of need. E.coli normally uses glucose as its respiratory substrate. However in some environments, glucose is sparse and it needs to use lactose instead. The lac operon represents the polypeptides that constitute the enzymes that breaks down lactose.

Compostion of Nephron

PCT○In the PCT fluid composition is altered by reabsorption 100% sugars, most salts and water○85% of water is reabsorbed• Descending Limb○the water potential decreased Salts added- Water removed•Ascending Limb○In the ascending limb water potential is increased○Salts are removed by active transport•Collecting Duct○In the collecting duct water potential is decreased again- Water removed

Explain the stages of mitosis

PMAT prophase,Metaphase,Anaphase,Telophase

Advantages of Myleination and its structure

Myelinated neurons can transmit action potentials more quickly than non-myelinated neurons○100-120 m/s•Non-myelinated neurons tend to be slower○2-20 m/s•Myelinated neurons carry signals from sensory receptors, to the CNS and from CNS to effectors•Carry signals over long distances•Enables rapid response to a stimulus by saltatory conduction

Explain anaerobic respiration in yeast

NAD+ must be recycled•Pyruvate undergoes decarboxylation and reduction to form ethanol•If •ATP yield is much lower in anaerobic respiration because the majority of it is formed in the oxidative phosphorylation — which requires oxygen as the final electron acceptor.

What happens in the decline phase of the growth curve.

Nutrient exhaustion • Increased levels of toxic metabolites• Microbial death exceeds numbers produced

What happens in the stationary phase of the growth curve.

Nutrient levels decrease• Toxic metabolites build up• Secondary metabolites produced• Growth rate slows• Population stabilizes• Organisms die at the same rate at which new individuals are being produced

Explain Transmission of nerve impulses along a neuron

Once the electrical impulse has been established, a local current exists in the cytoplasm of the neuron•This local depolarisation triggers neighbouring voltage-gated channels to open•Action potential travels in one direction along the cell

Name of stain that is used to visualize the chromosomes and DNA

Orcein stain

Blood flow in the Liver which type of Blood and how?

Oxygenated Blood from the aorta via Hepatic artery• Deoxygenated Blood from the digestive system via Hepatic portal vein○has digestive products Exit via the hepatic vein •Sinusoids○Oxy and deoxy blood mix in vessels called sinusoids○Join together to form the hepatic(central) vein○Blood flowing by sinusoids come into contact with the liver cells(Hepatocytes)

knee jerk reflex explained

Passes through spinal cord - is a spinal reflex•When they stretch, Patellar tendon attached by muscle spindles•Reflex is to contract the muscle immediately •Causing knee jerk reaction

What is photosynthesis?

Photosynthesis is the process by which plants and some other organisms convert light energy into chemical energy. The chemical equation for photosynthesis is:6CO2 + 6H2O + energy from photons *chlorophyll* C6H12O6 + 6O2 (takes place in chloroplast)

What happens in the link reaction?

Pyruvate is converted to acetyl coenzyme A, by oxidation (NAD+ -> NADH + H+) and decarboxylation (removal of CO2), in the Matrix

what is Apotosis and how does it work

Programmed cell death E.g. separation of human fingers — rather than being webbed Enzymes break down cell cytoskeleton•Cytoplasm becomes dense with organelles tightly packed•Cell surface membrane changes and blebs form•DNA breaks into fragments•Cell breaks into vesicles•These are taken up by phagocytosis•Very quick process

Ethene Funtion

Promotes fruit ripening

gibberellins function

Promotes seed germination • Promotes growth of stems

What are reflex actions?

Reflex actions are responses to external stimuli that do not require conscious coordination. They are immediate responses and their rapidity is achieved by bypassing the brain

Significance of reflexes for survival

Reflexes are key to survival • Provide effective protection from dangerous positioning/posture or incoming threats E.g. when you touch a hot object, you withdraw your hand — this is a reflex that prevents you from getting burnt

How does the Lac operon in the absence of lactose

Regulator gene is expressed and the repressor protein is synthesized○○One site binds to the operator region•Repressor protein binds to operator region○Covers part of the RNA polymerase binding site•RNA polymerase cannot bind to the promoter region○Structural genes are not transcribed to mRNA○Genes cannot be translated○Enzymes not produced

what are 3 treatments of Kidney failure

Renal Transplants• •Kidney surgically attached to blood supply and bladder•Patient take immunosuppressant drugs to prevent rejection Dialysis•Waste removed from blood by passing it over a dialysis membrane•Partially permeable membrane allows the exchange of substances between blood and dialysis fluid•Any excess substances diffuse out of the blood and into the dialysis fluid Treatment Haemodialysis•Blood from an artery is passed into a machine and dialyzed•Heparin added to avoid clotting•Performed at a clinic•Three times a week

What is respiration?

Respiration is a process that is carried out by all living organisms. It involves the oxidation of glucose to produce carbon dioxide and water, as well as the 'release' of energy — in the form of generating ATP from ADP and Pi. It is a form of heterotrophic nutrition — deriving nutrition from substances that contain organic molecules

What is positive feedback? (1)

Response that causes change to increase,Destabilizes the system, Usually more harmful•Does not lead to homeostasis•Can be useful in •Eg: childbirth (oxytocin )Uterine contractions

auxin function

Responsible for regulating plant growth• phototropsim - apical dominance Inhibits the growth of side shoots (lateral bud growth) •Inhibits leaf abscission(falling off)

How does the loop of Henle reabsorb water

Salts can be transferred from the descending limb to the ascending limb• Increases concentration of salts in the tubule fluid• Salts diffuse out into the surrounding medulla tissue• Medulla tissue has a very low water potential• Amount of water reabsorbed controls water potential of blood

Explain Gas Chromatography and Mass Spectrometry

Sample vaporized in the presence of a gaseous solvent•Passed down a long tube lined by an absorption agent•Each substance dissolved differently in the gas•Remains there for a unique and specific length of time•Eventually substance moves out of the gas and is absorbed into the lining•This is then analysed to create a chromatogram•Chromatograms of standard drugs and urine samples are taken, allowing unidentified substances to be easily identified

What do sensory receptors do?

Sensory receptors are specialised cell in the body that detect changes in the environment. They work by converting energy — acting as transducers from one form into electrical energy, which relays a signal to another part of the body.

cause of phototropism

Shoot bends towards a light source•Shaded side elongates faster than the lit side•Light causes cells to actively unload IAA•Unloaded from cells in light, towards those in shade•Causes the shoot to bend

What are the subdivision of the Peripheral Nervous System

Somatic Motor Neurons- Carry impulses from CNS to skeletal muscles which are under conscious control-Voluntary - e.g. muscle - Most neurons are myelinated- Connections only ever consist of one neuron○ Autonomic Motor Neurons- Carry impulses from the CNS to cardiac muscle, smooth muscle in the gut wall, blood vessels, glands and bladder- All of these are under unconscious control-Involuntary — e.g. intestinal smooth muscle contractions- Most neurons are non-myelinated- Connections have more than one neuronConnect at ganglion

Explain Genetic engineering

Specific gene is isolated and copied2. Gene is placed inside vector (e.g. plasmid)3. Vector carries gene to target cell 4. Recipient cell now has recombinant DNA and expresses newly acquired gene Isolating a required gene•mRNA coding for the specific gene is obtained •Reverse transcriptase forms a single strand of complementary DNA (cDNA) based off the mRNA•Adding primers and DNA polymerase catalyses the formation of double stranded DNA •Gene is then synthesised○Automated polynucleotide synthesis if gene sequence known○PCR if gene sequence unknown•DNA probe used to locate gene •Gene isolated by restriction enzymes

Explain glycolysis (4 stages )

Stage 1 — Phosphorylation•Occurs in cytoplasm•2 ATP molecules are hydrolysed, releasing phosphate group•Glucose 6-phopshate changes to fructose 6-phosphate•These sugars are activated, forming hexose 1,6-biphosphate Stage 2 — Splitting of hexosebisphosphate•Hexose bisphos is split into 2 triose phosphates Stage 3 — Oxidation of Triose Phosphate•2 hydrogen atoms removed from each triose phosphate•NAD combines with hydrogen, becoming reduced•Dehydrogenase enzymes usedStage 4 — Conversion to pyruvate•Triose phosphate converted to a molecule of pyruvate•2 molecules of ADP are phosphorylated to 2 molecules of ATP

What are the two types of Hormones

Steroid hormones and Protein hormones (Derived from amino acids)•Proteins are not soluble in the membrane•Steroid hormones can pass through and have a direct effect on DNA in the nucleus

How is the Cerebral cortex subdivided into 3 areas

Subdivided○Sensory Areas- Receive impulses indirectly from receptors○ Association Areas- Compare previous experiences to interpret and judge response ○Motor Areas- Sends impulses to effectors (your actions)

What stain is used to stain cell membranes/lipids

Sudan Red iii

Explain Type 2 Diabetes Mellitus

Sufferers can still produce insulin• Constantly high insulin levels due to sugar intake•Target cells' sensitivity to insulin declines•Beta cells die .thereby producing less insulin in the long term•Certain factors can increase the likelihood of diabetes:,Obesity,Diet high in sugars,Family history

describe the chloroplast structure

Surrounded by envelope• ○Folded into lamellae ○One granum = stacked thylakoids ○Between grana is the intergranal lamellae•The stroma is the fluid filled matrix, which contains the necessary enzyme to carry out the light dependent reactions

what is Acclimatization

Synapses may run out of transmitter substance and become fatigued•No longer respond to stimulus•Helps to avoid over stimulation .The creation of specific pathways within the nervous system is the basis of conscious thought and memory.

why are Nitrogenous compounds such as protein excreted and how?

The body is unable to store amino acids or proteins• its wasteful to excrete amino acids•transported to the liver and deaminated•The removed amine groups initially forms the very toxic ammonia•This is then converted to the less toxic urea, ornithine cycle which is transported to the kidneys for excretion•The remaining keto acid can be directly respired, or converted to a carbohydrate or fat

CNS

The central nervous system consists of the brain and the spinal cord.

kidney function / functional unit of kidney

The kidney's role is to filter blood and remove excess ions/water to produce urine. The functional unit of the kidney is the nephron.

What is the definition of PCR

The polymerase chain reaction, a technique used to amplify DNA which makes it more suitable for analysis. Millions of copies of sample of DNA are made and the base sequence is retained

what is a respiratory quotient (RQ) and how do you calculate it.

The respiratory quotient is an indication of how aerobic the respiration is that is taking place. The formula for RQ: :RQ = CO2 produced ÷ O2 produced

What are the two Cell signalling systems

There are 2 major systems of communication: Neuronal System• via Network of neurons• Quick signals• Rapid responses Hormonal System•Uses blood to transport signals•Endocrine glands secrete hormones directly into blood•Carried all over the body•recognized by specific target cells•Enables long-term responses to be coordinated•Specific target cells have receptors that have a shape that is complementary to the shape of the hormone

What is a primary pigment, eg?

These are found at the centre of the Photosystem •They can absorb energy from the sun or from accessory pigments○E.g. Chlorophyll A peak light absoprtion (680,700,450)

Cytokine function

To Promote cell division

How do you treat type 1 and 2 respectively

Type 1○Insulin injections○Blood glucose levels are monitored• Type 2○Diet controlled and monitored

explain the Pyrosequencing method

Type of high throughput sequencing dInvolves synthesising a single strand of DNA complementary to the one being sequenced •Process:○DNA cut into fragments of 300-800 base pairs ○Fragments are degraded into single-strand DNA (ssDNA)○Fragments incubated with primer, APS,luciferin, and several enzymes, including DNA polymerase○Nucleotides added are ATP, TTP, CTP, GTP ○Nucleotides form chains complementary to the DNA fragments ○They dephosphorylate: i.e. ATP -> adenosine; TTP thymine, etc ○APS + pyrophosphate ATP ○Visible light is released in this reaction and detected by a camera ○Light patterns detected indicate amount of ATP and therefore DNA sequence ○10-hour run = 400 million bases are read

Commercial use of Auxins (3)

Used as a rooting powder for cuttings• Can promote the growth of seedless fruit in unpolluted flowers Artificial auxins can be used as herbicides• Promote and inhibit fruit dropping

Sturcture and function of adrenal cortex

Uses cholesterol to produce steroid hormones○These have an important role in the body- Secretes mineralocorticoids which help to control the concentration of sodium and potassium in the blood- Secretes glucocorticoids which help to control the metabolism of carbohydrates and proteins in the liver

Explain peritoneal dialysis

Uses filter in the abdominal membrane•Permanent tube implanted in the abdomen•Dialysis solution fills space between organs and membrane•Solution drained after several hours•Patient able to walk around•Can be carried out at home

Explain the process of muscular contraction

When a muscle is at rest, Ca concentration surrounding the fibrils is low•Under these conditions, tropomyosin sits in the myosin binding sites and the contractile mechanism is 'off'• the muscle is stimulated, a wave of depolarisation passes in through the T system•When the impulse reaches the SR it causes the release of Ca ions•Ca concentration increases•Ca ions bind to troponin causing it to change shape•Tropomyosin moves out of the myosin binding site on the actin filaments•Actin is now 'on'•ATP binds to the myosin and is hydrolysed to ADP and Pi, both of which remain bound to the myosin head•Pi is released, changing the shape of the myosin head and allowing it to form cross-bridges•ADP is released causing the myosin head to tilt and pull the actin filament over the myosin filament. called a power stroke.•At the end of the power stroke, the ATP binds to the myosin head and the cross bridges are broken•If Ca concentration remains high, the cycle will be repeated

What is Cell signalling?

When cells communicate by signalling, one cell releases a chemical•This chemical is detected by another cell•The second cell then responds to this signal

Explain anaerobic respiration in animals

Without oxygen, Link Reaction, ETC and Krebs cycle stop•Glycolysis can still occur•NAD+ is recycled•H atoms need to be removed from NADH molecules•Pyruvate is used as an H acceptor•In muscle cells, pyruvate is converted to lactic acid on accepting the H atom•Lactic acid is taken to liver•It is re-converted to pyruvate•This enters the link reaction in liver cells, where it is aerobically respired

What is a point mutation? what are the types of these (3)

a alteration in a single base pair in DNA silent-neutral No change in amino acid sequence of polypeptide•, Nonsense mutation○The mutation changes the code turning the triplet into a stop codon○Instructs the end of polypeptide synthesis○The polypeptide is shorter than it would normally be, missense Missense mutation○The mutation changes the code for 1 amino acid○1 amino acid in the sequence is changes •

lac operon

a gene system whose operator gene and three structural genes control lactose metabolism in E. coli transcriptional level regulation lactose permease and beta galactoisde

definition of population

a group of organisms of the same species who live in the same place at the same time and can breed

Explain what a Nastic response and give an example of a plant

a non-directional response to stimuli, e.g. thigmonasty — Mimosa pudica plant responds to touch by folding its leaves.

Explain what photophosphylation in the light dependent stage

a photon hits a chlorophyll , energy is transferred to 2 electrons exciting them○Electrons captured by electron carriers and passed along electron carriers○Energy released to pump protons across thylakoid membranes○Proton gradient is formed and protons flow down the concentration gradients through ATP channels○This is chemiosmosis○This produces a force which joins ADP and Pi to form ATP- ATP is used in the light independent stage of the reaction- The making of ATP using light energy is called photophosphorylation

What if Grafting

agrobacteria tumifaciens used to transfer Ti plasmid( plant is cut and bound to a prized existing stem

explain the transfer of action potential in a motor unit

activated by an action potential release Ach by exocytosis neurotransmitter bind to post junction membrane produce an action potential in the muscle

Distal Convulted Tubule (DCT) function

adjust conc of ions with hormones , no brush border , regulate pH

Methods of enzyme immobilisation

adorptions- adsorbed top inert matter covalent bonding-bound to support materiel entrapment- trapped in porous beads membrane separation, obvious

hormones of the endocrine system

adrenaline, noradrealine, thryoxine all increase heart rate.

what are the two ways of cloning mammals

adult cell cloning and embryo splitting (ES- zygote created by IVF new embryo devlpoed by diffentiation is split and implanted into different surggoates adult cell clone. a somatic cell nucleus and an egg + electric

definition of community

all the populations of different species living in the same place at the same time

What does glucagon do? (cells?)

alpha cells raises blood glucose levels by secreting Glucagon to Hepatocytes.( releases glycogen from muscle into glucose in the blood stream)

Explain Nitrification

ammonium(NH4)-Nitrites(NO2-)-Nitrates (NO3-) catalyzed by Nitrobactor and Nitrosimonas lightning converts atmospheric nitrogen into ammonium (nitrogen fixing)

What is a respiratory substrate

an organic substance that can be used for respiration Glucose in main respiratory substrate Proteins have a Slightly higher energy yield Triglyceride hydrolysed to glycerol•Glycerol can be converted to glucose•Fatty acids are long chain hydrocarbons•can produce lots of ATP by chemiosmosis during oxidative phosphorylation

ares to collect meristematic tissues in plants

areas of undifferentiated cells apical buds tips of shoots and roots auxiliary buds (the angle between the leaves ans the stem) vascular cambium

What is genetic engineering/ recombinant DNA

artificially alternating the genome recombinant DNA transfer the DNA to another organism(staggered cuts and sticky ends) with restriction endonuclease

What happens in non cyclic phosphorylation

at Photosystem 1 and 2 , at ps2 photolysis enzyme breakdown water to H+ions and oxygen with light also, red nadp is genarated

How is Insulin secreted

beta cells contain Ca and K ion channels•K ion channels normally open•Ca ion channels normally closed•K ions diffuse out, making the inside more negative•When glucose conc outside is high, glucose molecules diffuse into the cells•Glucose metabloized to make ATP•Extra ATP causes K ion channels to close•K cant diffuse out•This alters the p.d. across membranes, making the inside less negative•Change in p.d. opens the Ca ion channels•Ca ions enter the cell•Cause insulin vesicles to move to the cell surface via Exocytosis

Benefits and risks of GM Bacteria

better than pig insulin, less chance of rejection less ethical concern , can be used as a gene library, can be produced quickly , can be antibiotic resistant and stored in large quantities

how is water moved int he apoplast pathway

between the cellulose cell walls until the Caspian strip as it is impervious due to suberin forcing the water into symplast.

function of liver

bile production detoxification breakdown erythrocytes stores glycogen produces plasma proteins

where are stem cells found (3)

bone marrow. embryo, cambium, lungs , heart brain

why use cloned plants

can grow specific characteristic, higher yield , flower colour, pesticide resistant preserve rare breed uniform appearance(easier to harvest) o diseases resistant infertile plants can be reproduced but all susceptible to one disease , lacks genetic variation

what is the movement of water in the stem

cohesion, adhesion tension stay together ,sticks to xylem vessel in a continuous line of water

structure of xylem

dead cells forms by lignin water always go up boarded pits allow for lateral movement of water transpiration of water vapor.

how is alcohol break down in the body

converted to ethanol by ETHANOL DEHYDROGENASE, then it is reduced from ethanoic acid to acetate to acetyl co enzyme A. Nad is limited and lipids are broken down secondary which leads to fatty liver

what does adenyl cyclase do

converts ATP to cAMP , the secondary messenger molecules causes an effect in the cell stimulating enzyme action

5 effects of adrenaline

converts glycogen to glucose in blood increasing lung breathing rate in digestive system vaso constricts vasodilate (more blood to muscles) pulpils dilate increasing width of bronchial , smooth muscle , increasing air flow

explain the nature of the genetic code

degenerate-multiple triplets can code for the same amino acid universal-all living organism have the same bases to code for them non overlapping-the bases are read three bases at a time and they do not carry over

PCR stages

denaturation(95.c), annealing(55-68.c)Taq Polymerase binding of primers , synthesis 72'c optiumum temp for Taq

what dieses are recissive and dominant

dominant- huntingtons , polydactyl recessive-cystitis fibrosis ,albinism, pku

what is Q10 rule

double in the rate of reaction every 10 degrees until the optimum is reached

averge atp from reduced nap, fad

fad-1.5 atp red -2.5 atp 32 atp molecules in total in matrix to inter membrane space (proton motive force) oxygen is final electron acceptor

what do glucocortcoids do, and mineralcorticoids

gluco-controls metabolism of carbs and proteins, minero controls sodium and potassium conc in blood

Glycolysis in detail

glucose phosphorlyated(2 ATP used) -fructose then hexose bisphospahte then 2 triose phsopahte 4 atp produced 2 nad reduced

how does the loop of Henle function

hair pin counter current multiplier in descending limb H20 pumped down in ascending limb ions actively pumped out salts diffuse into medulla and tissues so ions the body needs is reabsorbed.

explain the structure of the autonomic nervous system

has swellings called ganglia , they are myleinated neurons transfer ap to CNS to muscle

Before Depolarization

insiude -70mv resting potential 3 NA- in 2K+ out change of charge iside +30-mv generates and action potential,sodium channels open sodium enters and depolsies the cell (faccilated diffusion)

explain post transcriptional regulation

introns-inexpresed , extron- expressed using gene splicing with restriction endonuclease

Explain non-cyclic photophosphorylation

involves both PS1 and PS2○Light strikes PS2, exciting a pair of electrons○Electrons leave the chlorophyll molecule from the primary pigment reaction centre○Electrons pass along the chain of electron carriers ○Energy is released, which is used to synthesize ATP, causing the release of 2 electrons○Electrons from oxidized PS2 replace those lost from PS1○Electrons from photolysed water replace those lost from PS2○Protons fro photolysed water take part in chemiosmosis, to make ATP○They are captured in NADP in the stoma and used in the light-independent stage

What stain is ,used to stain starch

iodine (stains starch blue/black)

difference between lactate fermentation

lactate-one enzyme used Lactate dehydrogenase reversible reoxised lactate at the liver alcohol fermentation pyruvate de carboxylase and ethanol de hydrogenase co2 released , not reversible

The lac operon in E. coli

lactose binds to repressor proteins causing a conformation change so they can bind to the promoter region blocking the operator region, so structural units can be transcribed

advantages and disadvantage of enzyme immobilization

less enzyme lost can be reused downstream processing cost reduced better temperature stability can be expensive contamination means disposal(expensive)

adaptation of xerophytes

less stomata, sunken pits ,waxy cuticle , curled leaves( reduces loss by convection)

explain all the stages in the cell life cycle

mitosis plus +interphase , G1 , S(DNA synthesis),G2

What are hormones?

molecules produced and secreted by endocrine glands directly into the blood. They act as messengers and transport signals from one gland to a specific target tissue or organ to produce a desired effect.

Explain the founder effect

most common in small populations. The founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population

defintion of mutuation and karyotype

mutation- random change in the genetic material Karotype - a picture a set of chromosome ( down syndrome add an extra chromosome

Nephron structure (6)

nephrons spread across the cortex and medulla of the kidney. Blood enters the organ via the renal artery and exits via the renal vein. In between, it passes through tiny capillaries that surround the continuous tube constituting the nephron. Function•Filter out waste products Bowman's Capsule-Ultrafiltration ,Filter blood •Proximal Convoluted Tubule (PCT) selective reabsorption Re-absorbs valuable substances, such as glucose• Loop of Henle Creates low water potential in the medulla○Allows water to be reabsorbed•Distal Convoluted Tubule (DCT)○osmoregulation○Varies the amount of water reabsorbed into the Blood

Prokaryotic features(5)

no membrane bound organelles, 70s ribsomes , plasmids , binary fission , mesosomes , peptidodcylan flagella

What is osmoregulation?

osmosis- tendency for water to move from one are to another .contol of water potential by hypothalamus and pituitary gland adh to collecting duct

Hardy-Weinberg equilibrium

p^2 + 2pq + q^2 = 1 p + q = 1. ff=q^2 , Ff =2PQ p^2=FF

PNS

peripheral nervous system Contains all the nerves that are not in CNS•This includes motor nerves which can be subdivided

feature of water

polar-has weak areas of attraction(oxygen has more electrons) high specif heat capcity 4.2kj/kg high latent heat of evapouration very cohesisve due to polar nature very adhesive (polar) univeral solvent (forms hydration shells around ions most dense at 4'c

explain repolarzation

potassium ions open potassium rush out , more negative the normal becomes hyperpolarised , pumps reestablish resting potential

Explain somatic cell gene therapy

replacing a faulty allele with a functioning allele inserted into body cell using vectors lika bacteria plasmid micro injection electroporation liposome- lipid membrane containing a functional alles HAC (human artificial chromosome) adding insulin gene into beta islet cells

Outline how bacteria can be gentically modifed to produced renin

restriction endonuclease can cut out a section of lamb dna , staggered cut for complementary base pairing plasmid cut with same restriction enzyme. gene inserted , DNA ligase joins sugar phosphate backbone plasmid inserted into bacteria by liposome , trangenic bacteria developed in a culture

what is a DNA probe/applications of PCR

short section of DNA complementary to DNA sequence/forensic science, paternity tests,genetic relationships, custody disputes(diagnose cystic fibrosis , tissue typing

Cardiac muscle properties

similar to skeletal muscle, but with longer duration of contraction• myogenic(initiates its own contraction)has nerve from autonomic •Dark areas are intercalated discs○Cell membranes that fuses to form gap junctions○Ions are able to diffuse easily through this network of interconnections• has Striated muscle

Diffence between somatic and autonomic nervous

somatic- effectors under voluntary control targets skeletal muscle Autonomic- controlled by medulla oblongata , involuntary functions breathing, digestion splits into symp(adren) and parasymp(ACH)

effects of adrenaline and cortsol

stimulates target organs , cortisol increases blood pressure and blood glucose and suppresses the immune system

explain primary succession

the colonization a new area by a pioneer species most probably lichen can survive hostile environment , high germination rate, asexual population,drop nutrients on the ground

Explain co-dominance.

the phenotypes of both alleles are clearly expressed in the hetrozygous condition eg (roan) and 3 immunoglobin genes I'a,I'B,

What is DNA profiling and explain the process

the practice of DNA analysis that confirms the identity of an individual. Process:•DNA obtained from individual — e.g. mouth swab•DNA cut by restriction enzymes at specific sites •Fragments are separated by gel electrophoresis•Banding pattern can be seen•Banding pattern compared to another individuals' which has been treated with the same restriction enzymes•Related individuals will have more similar banding patterns(may use PCR)

how do marker genes work

those ex planted vector genes are put in a medium with bacteria. the marker genes have antibiotic resistance so they survive.

vectors for genetic engineering

tranfer dna into plasmds agrobacterium tumifacnens( plants) virus plasmid , liposome, micro injection, electroporation virus

How does tRNA work?

trna has an anticodon that binds to mrna that is read two triplet bases at a time forms a peptide bond(every three bases is a codon)

secondary succession

type of succession that occurs in an area that was only partially destroyed by disturbances recolonizing after earlier community was removed like (natural disaster)

What is bioinformatics? and what is t squared test

understand how genes work(large amount of data) to understand how genes work and fix genetics/ T squared how different two points are from each other

collecting duct function

water moves down the pelvis , regulated by ADH negative feedback release of aquaporins

what is positive co operativity

with oxy association where a conformational change takes place to form the first oxhemoglobin it's is easier for haem to ascociate oxygen until the last oxygen (4 oxygen total)

reason for loss in biomass transfer

• Biomass is lost during transfer for a variety of reasons• Not all energy absorbed goes into producing biomass• Some lost in movement, immunity etc.• Some lost during respiration as heat energy• Not all energy is absorbed between levels• Some food can't be digested, biomass lost in faeces and urine• Not all of the organism is eaten, e.g. bones, wood• Not all some die and decay transferred to decomposers

describe the features of a continuous culture

• Useful and waste products continually removed• Some bacteria are removed• Nutrients continuously added• Difficult to set up• More efficient as the fermenter operates continuously

Commercial of Cytokines (2)

•Delay leaf senescence• Prevent yellowing of lettuce leaves• Help mass produce plants○ Promote bud and shoot growth○Produces short shoot with a lot of side branches

Explain some Chloroplast adaptations (3)

•Many grana provide a large surface area for photosynthetic pigments •Photosynthetic pigments are arranged into photosystems• Proteins embedded in grana to hold the photosystems in place

Explain the process of PCR

•Separating DNA strands○Heated to 95c○Causes strands to separate•Primers○Cooled to 55c○Primers are able to attach•DNA replication○Heated to 72c○DNA replication can now occur•Thermostable DNA polymerase○Taq polymerase used○Thermus aquaticus○Bacteria that lives in deep, warm oceans •Overall Process○Everything added restricon enxyme , nucleotides Allow DNA to replicate○DNA is replicated○Heated again and repeat the process

Commercial use of Ethene (2)

•Speeds up fruit ripening •Ethene can be inhibited to prevent fruit ripening

Skelatal muscle properties

•Voluntary muscles• leads to the movement of the skeleton•multi nucleated •Cell surface membrane is the sarcolemma•Cell cytoplasm is the sarcoplasm•Sarcoplasm contains:○Many mitochondria○Extensive sarcoplasmic reticulum○Myofibrils- Contractile elements- Contain smaller units called sarcomeres- Actin and myosin filaments•Called 'striated muscle' because striped appearance

Explain The Fred Sanger method for sequencing

•interupted PCR(add modified nucleotides bases dideoxynucleotides prevent addition of nucleotides)(may have flourscenct or radioactive isotope •electropherosis