BIOLOGY MODULE 2 (papers 1,2, & 3) Flashcards

Question

what is the chloroplast?

Answer 1

- small flattened structure - surrounded by double membrane - contains thylakoid membranes stacked to form grana - grana linked together by lanellae

Answer 2

- site of photosynthesis - parts of photosynthesis happen in grana and others in stroma

Answer 3

- small hollow cylinders made of microtubules - found in animal cells and some plant cells

Answer 4

involved in separation of chromosomes during cell division

Answer 5

- small hair-like structures found on surface membrane of animal cells - cross section = 9 microtubules + 2 microtubules inside

Answer 6

- microtubules allow cilia to move - moves substances along cell surface

Answer 7

- longer than cilia - stick out from cell surface - cross section = 9 microtubules + 2 microtubules inside

Answer 8

- microtubules contract to make flagellum move - motors to propel cells forward

Answer 9

1. ribosomes on RER make proteins that are excreted or attached to cell membrane, free ribosomes make proteins stay in cytoplasm 2. new proteins produced at RER are folded and processed in RER 3. they're transported from ER to Golgi in vesicles 4. proteins enter more vesicles to be transported around the cell

Answer 10

- microtubules & microfilaments support cells organelles - strengthen and maintain cell shape - responsible for movement of materials within cells - proteins in cytoskeleton allow cell to move

Answer 11

*eukaryotes* vs **prokaryotes** *larger* **smaller** *linear DNA* **circular DNA** *nucleus - DNA inside* **no nucleus - DNA in cytoplasm** *no cell wall, cellulose in plants, chitin in fungi* **polysaccharide cell wall - not cellulose/chitin** *many organelles (mitochondria)* **few organelles (no mitochondria)** *flagella made of microtubules* **flagella made of flagellin** *larger ribosomes* **smaller ribosomes**

Answer 12

- prokaryotic - to small to see internal structure with normal microscopes

Answer 13

magnification = image size/actual size

Answer 14

mm x1000 = micrometers micrometers / 1000 = mm

Answer 15

- uses light - lower resolution than electron microscope - looks at whole cells/tissues - magnification = x1500

Answer 16

- uses laser beams to scan specimen & tagged with fluorescent dye - laser causes dye to fluoresce (give off light) - light focused through a pinhole - image is 3D - used to look at objects at different depths - higher resolution than light microscope

Answer 17

- uses electromagnets to focus beam of electrons transmitted through the specimen - denser parts of specimen absorb more electrons - high resolution images - only used on thin specimen - only shows inside of cell - 2D

Answer 18

- scans beam of electrons across specimen - shows surface and inside of specimen - can be 3D - lower resolution than TEM

Answer 19

light - resolution: 0.2 µm - magnification: x1500 TEM - resolution: 0.0002 µm - magnification: x >1,000,000 SEM - resolution: 0.002 µm - magnification: < x500,000

Answer 20

- use dye (e.g. methylene blue/eosin) - increases contrast - different stains are used to make different things show up

Answer 21

- objects are dipped in solution of heavy metal - metal ions scatter electrons & increase contrast

Answer 22

- cut specimen - place on slide - cover with cover slip

Answer 23

- pipette small drop of water on slide - place with cover slip at an angle to remove air bubbles - then add stain to one edge of cover slip

Answer 24

- fitted onto eyepiece - numbers with no units

Answer 25

- is a microscope slide with an accurate scale (has units) - placed on the stage - used to work out divisions on eyepiece graticule at a particular magnification - helps to measure specimen

Answer 26

- reactant in chemical reactions - solvent (some substances dissolve in it) - transports substances - helps with temperature control - high specific heat capacity - high latent heat of vaporisation - is a habitat

Answer 27

- 1 oxygen atom (+) and 1 hydrogen atom ( +) - water is polar - slight negative oxygen attracts positive hydrogen (hydrogen bonding)

Answer 28

- Hydrogen bands give water high specific heat capacity (they absorb lots of energy) - hydrogen bonds give water high latent heat of evaporation (takes lots of energy to break H bonds - polarity makes it very cohesive (water molecules stick together + helps water flow) - polarity makes it a good solvent (slight positive end of water molecule attracted to negative end of ion and vice verse, surrounding/ dissolving the ions) - less dense when is solid, ice floats & doesn't affect organisms)

Answer 29

Monosaccharides

Answer 30

- made from polymers (molecule made from many monomers banded together) - Monomers that make carbs are monosaccharides - glucose is a monosaccharide with 6 carbon atoms - 2 forms a glucose (alpha and beta)

Answer 31

- Function: main energy source in plants and animals - structure makes it soluble so easily transported - its chemical bonds contain lots of energy

Answer 32

Monosaccharide with 5 carbon atoms (pentose monosaccharide)

Answer 33

Carbon, hydrogen, carbon - for every carbon atom, 2 hydrogen atoms and 1 oxygen atom

Answer 34

- Monosaccharides are joined by glycosidic bonds - during synthesis, a H atom on one monosaccharide baas to an OH group of another releasing water (conversation)

Answer 35

- Main energy storage material in plants - plants store excess glucose as starch - starch is a mixture of 2 polysaccharides of alpha glucose - amylose and amylopectin - is insoluble in water so doesnt enter cell by osmosis - makes it good for storage

Answer 36

- long unbranched chain of alpha glucose - coiled structure due to angles of glycosidic bonds - makes it compact so good for storage and can fit more in

Answer 37

- long branched chain of alpha glucose - side branches allow enzymes to get at glycosidic bonds easily - means glucose can be released quickly

Answer 38

- animal cells get energy from glucose but store excess glucose as glycogen - branched chain of alpha glucose so glucose can be released quickly - compact molecule so good for storage

Answer 39

- long unbranched chains of beta-glucose - forms straight cellulose chains - chains linked by hydrogen bonds to form microfibrils - provides structural support for cells

Answer 40

- kind of lipid - complex molecules - large molecular mass - contain carbon, hydrogen and oxygen - one molecule of glycerol and 3 fatty acids attached to it

Answer 41

- tails made of hydrocarbons - hydrophobic tails - makes lipids insoluble in water

Answer 42

- contain ester bonds between each fatty acid and glycerol - formed by condensation reaction - triglycerides are synthesised through esterification - triglycerides break down when the ester bond is broken - ester bonds broken in hydrolysis reaction

Answer 43

HYDROCARBON TAILS: saturated - dont have any double bonds between carbon atoms unsaturated - have at least one double bond between carbon atoms, causing chain to kink

Answer 44

- both macromolecules - fatty acid head replaced with phosphate group - phosphate groups is hydrophilic and tails are hydrophobic

Answer 45

- long hydrocarbon tails contain lots of chemical energy - lots of energy is released when they're broken down - insoluble so dont cause cells to swell (water in by osmosis) -triglycerides bundle together, tails face inwards to shield from water

Answer 46

- hydrophilic heads, hydrophobic tails - form double layer with heads facing out - centre of bilayer is hydrophobic so water-soluble substances cant easily pass through it

Answer 47

- hydrocarbon ring structure attached to hydrocarbon tail - small size and flattened shape - allows cholesterol to fit between phospholipid molecules - at high temp, they bind to tails and so pack more closely - reduced fluidity - low temp, prevents phospholipids packing too close to increases membrane fluidity

Answer 48

helps regulate fluidity of cell membrane by interacting with phospholipid bilayer

Answer 49

- polymers - monomers of proteins - dipeptide bond formed between amino acids - made of 1 or more polypeptides

Answer 50

- all amino acids have a carboxyl group and amino group attached to carbon - contain variable R group - all contain H, C, O, N and sometimes S

Answer 51

- peptide bonds to form dipeptides & polypeptides - condensation reaction when bonds are formed - hydrolysis reaction when bonds are broken

Answer 52

- sequence of amino acids in polypeptide chain - change in amino acids may change structure of whole protein

Answer 53

- polypeptide chain doesnt remain flat & straight - H bonds form between nearby amino acids in the chain - makes it coil into alpha helix or beta pleated sheet

Answer 54

- coiled or folded chain coiled and folded further - more bonds form between polypeptide chain - proteins made of single polypeptide chain, tertiary structure forms final 3D structure

Answer 55

- how multiple polypeptide chains assemble together - proteins made of 1+ polypeptide chain, quaternary structure is final 3D structure e.g. Hb

Answer 56

peptide bonds

Answer 57

hydrogen bonds

Answer 58

ionic bonds - attraction between +/- R groups disulfide bonds - cysteine binds to sulfur hydrophobic & hydrophilic interactions - hydrophobic R groups clump together so hydrophilic R groups pushed to outside (affects folding) hydrogen bonds

Answer 59

- peptide - hydrogen - ionic - disulfide - hydrophobic & hydrophilic interactions

Answer 60

- round and compact - hydrophilic R group pushed to outside of molecule caused by hydrophobic interactions in tertiary structure - soluble so easily transported

Answer 61

- carries oxygen around the body in RBCs - is a conjugated protein (protein with non-protein attached (prosthetic group)) - prosthetic group is haem, containing iron, which O binds to

Answer 62

- hormone secreted by pancreas - regulated blood glucose levels - transported in blood - has 2 polypeptide chains, held by disulfide bonds

Answer 63

- enzyme - catalyses breakdown of starch in digestive system - single chain of amino acids - has alpha helix AND beta pleated sheet structure - most enzymes are globular proteins

Answer 64

- insoluble and strong - structural proteins

Answer 65

- found in animal connective tissue - strong molecule minerals can bind to it to increase rigidity

Answer 66

- found in external structures of animals - flexible or hard and tough

Answer 67

- found in elastic connective tissue - is elastic so allows tissues to return to original shape after being stretched

Answer 68

- don't contain carbon - have an electric charge

Answer 69

- calcium - sodium - potassium - hydrogen - ammonium

Answer 70

- nitrate - hydrogencarbonate - chloride - phosphate - hydroxide

Answer 71

- all monosaccharides and some disaccharides - add benedicts and heat in water bath - positive test = coloured precipitate - higher conc of reducing sugar, further colour change goes blue - green - yellow - orange - red - more accurate way: filter solution and weight precipitate

Answer 72

- to test for non-reducing sugars they must be broken down into monosaccharides - add dilute HCl and heat in water bath until boiling - neutralise with sodium hydrocarbonate - then carry out ordinary benedicts test - positive = coloured precipitate, negative = remains blue

Answer 73

- test strips coated in reagent * dipped in solution - change colour if glucose is present - chart indicated glucose concentration

Answer 74

- add iodine dissolved in potassium iodide to sample - positive = brown/orange to blue-black - negative = stays brown/orange

Answer 75

- solution needs to be alkaline so add drops of sodium hydroxide solution - add copper sulfate solution - protein present = purple - no protein = biuret stays blue

Answer 76

- shake test substance with ethanol & pour solute into water - lipid present = milky solution - more lipid = more milky - no lipid = solution stays clear

Answer 77

- benedicts reagent and a colorimeter - colorimeter measures strength of coloured solution - helps measure conc of blue benedicts solution left after test - paler = more glucose = lower absorbance

Answer 78

- used to separate & identify things in a mixture - can be used to separate & identify biological molecules - 2 types: paper chromatography and thin layer chromatography

Answer 79

- where molecules can move - mobile phase is a liquid solvent (ethanol/water)

Answer 80

- where molecules can't move - stationary phase is the paper in paper chromatography - stationary pahse is thin layer of solid on glass in thin layer chromatography

Answer 81

- mobile phase moves through or over stationary phase - components of mixture spend different amounts of time in mobile & stationary phase - longer time in mobile phase travel further - time spent in each phase is what separates out components of mixture

Answer 82

- ratio of distance travelled (d.t.)by solute to distance travelled by solvent Rf = d.t. by solute/d.t. by solvent

Answer 83

nucleic acids

Answer 84

- biological molecule - made from pentose sugar, nitrogenous base, phosphate group - monomers that make up DNA and RNA - ADP and ATP are nucleotides used to store and transport energy in cells

Answer 85

- deoxyribose sugar - each DNA neucleotide has the same sugar and phosphate group - has 4 possible bases (A,C,T,G) - molecule of DNA has 2 polynucleotide chains

Answer 86

- adenine and guanine - base containing 2 carbon-nitrogen rings joined together - larger

Answer 87

- thymine and cytosine - base containing 1 carbon-nitrogen ring - smaller

Answer 88

- ribose sugar - has a phosphate group - has 4 possible bases (A, U, C, G) - made of single polynucleotide chain

Answer 89

phosphorylated nucleotides

Answer 90

- add one or more phosphate groups to it - ADP has adenine, ribose and 2 phosphate groups - ATP has adenine, ribose and 3 phosphate groups

Answer 91

- provides energy for chemical reactions in the cell - is synthesised from ADP and Pi using energy

Answer 92

ATP and a phosphate bond

Answer 93

- join between the phosphate group of one and the sugar of another via condensation reaction - this forms a phosphodiester bond - chain of sugars and phosphate = sugar-phosphate backbone - polynucleotides can be broken down into nucleotides by hydrolysing phosphodiester bonds

Answer 94

- 2 DNA polynucleotide strands join together by hydrogen bonding between bases - complementary base pairing - 2 hydrogen bonds form between A-T - 3 hydrogen bonds form between C-G - antiparallel chains twist

Answer 95

1. break up cells in sample e.g. blender 2. make solution of detergent, salt and distilled water 3. add broken up cells to beaker containing detergent and incubate beaker 4. place beaker in ice bath & filter mixture 5. add protease enzymes to break down some protein bound to DNA 6. dribble col ethanol down side of tube so layer is formed on top of DNA-detergent mixture 7. leave mixture and DNA will form white precipitate

Answer 96

1. DNA helicase breaks H bonds between 2 polynucleotide DNA strands - unzips strands 2. each original strand acts as a template for a new strand and floating nucleotides join exposed complementary bases 3. nucleotides of new strand joined together by DNA polymerase to form sugar-phosphate backbone 4. hydrogen bonds form and strands twist to form double helix 5. each new strand contains one original and one new strand

Answer 97

- semi-conservative = half the strands of new DNA are from original - very accurate - sometimes random, spontaneous mutations occur and change DNA base sequence and can alter sequence of amino acids and produce an abnormal protein

Answer 98

- different proteins have different numbers and order of amino acids - order of nucleotide bases determines order of amino acids in a protein - each amino acid is coded for by a triplet in a gene - different sequences of bases code for different amino acids

Answer 99

sequence of DNA nucleotides that codes for a polypeptide

Answer 100

- DNA is found in nucleus of cells but organelles that make proteins are in cytoplasm - DNA is too large to move out the nucleus so a section is copied into mRNA (TRANSCRIPTION) - mRNA leaves nucleus and joins with ribosome in cytoplasm (TRANSLOCATION)

Answer 101

- made in nucleus - 3 adjacent bases = codon - carried genetic code from DNA in nucleus to cytoplasm where its used to make protein for translation

Answer 102

- found in cytoplasm - has amino acid binding site at one end and sequence of 3 bases at other end (anticodon) - carried amino acids to ribosomes during translation

Answer 103

- forms 2 subunits in a ribosome (large & small) - ribosomes move along mRNA strand during protein synthesis - rRNA in ribosome helps catalyse formation of peptide bonds between amino acids

Answer 104

- a sequence of codons in DNA or mRNA - base triplets are read in sequence - triplets dont share or overlap bases - is degenerate (more combinations of triplets than amino acids) - have start/stop codons = tells cell when to star/stop protein production - is universal = same specific base triplets code for same amino acids in all living things

Answer 105

1. starts when RNA polymerase attaches to DNA double helix at start of gene 2. H bonds between 2 strands break, DNA uncoils 3. one strand is used as a template to make an mRNA copy 4. RNA polymerase lines up free RNA nucleotides & base pairing means mRNA strand is complementary to DNA (except T & U) 5. once RNA nucleotides pair with bases on DNA, they form an mRNA molecule 6. RNA polymerase moves along DNA separating strands and assembling mRNA 7. H bonds between uncoiled strands of DNA re-form once RNA has passed so strands coil back 8. when RNA polymerase reaches stop codon, it detaches from DNA 9. mRNA moves out nucleus though nuclear pores and attaches to ribosome in cytoplasm

Answer 106

- occurs at ribosomes in cytoplasm 1. mRNA attaches to ribosome and tRNA molecules carry amino acids to ribosome 2. tRNA molecule attaches to mRNA by base pairing 3. second tRNA molecule attaches itself to next codon in mRNA 4. rRNA in ribosome catalyses formation of peptide bonds between amino acids attached to tRNA molecule so first tRNA molecule moves away 5. third tRNA molecule binds to next codon on mRNA so second tRNA molecules moves away 6. process continues until reaches stop codon 7. polypeptide moves away from ribosome

Answer 107

- speed up chemical reactions by acting as biological catalysts - catalyse metabolic reactions at cellular levels and for whole organism (e.g. digestion) - action can be intracellular or extracellular - are globular proteins - active site is specific shape (where substrate binds) determined by tertiary structure

Answer 108

- catalase - hydrogen peroxide is the toxic by-product of many cellular reactions - catalase works inside cells to breakdown hydrogen peroxide into oxygen and water

Answer 109

- amylase (digestion) - found in saliva, secreted by the mouth in salivary glands - catalyses hydrolysis of starch and maltose in the mouth

Answer 110

- make reactions happen at a lower temperature - this speeds up rate of reaction - formation of enzyme-substrate complexes lower activation energy

Answer 111

- the substrate fits into a specific enzyme - enzyme and substrate do need to fit together in the first place

Answer 112

- as substrate binds, active site changed shape slightly to fit substrate more closely - substrate deosnt need to be the right shape for the active site, but has to make the active sit change shape in the right way

Answer 113

- rate increases with temperature - more heat = more kinetic energy = enzymes more likely to collide with substrate - when temp goes above optimum, enzymes bonds break and it denatures so cannot function as a catalyst

Answer 114

- Q10 value for a reaction shows how much the rate of a reaction changes when the temperature is raised by 10°C - equation: Q10 = R2/R1 *R2 = rate at higher temperature *R1 = rate at lower temperature - most enzyme controlled reactions have a Q10 of 2

Answer 115

- more enzyme molecules = more likely a substrate molecule will collide and form an enzyme-substrate complex - increasing conc of enzyme increases rate of reaction - if substrate is limited, adding more enzyme has no further effect

Answer 116

- higher substrate concentration = faster reaction (more substrate molecules mean more collisions) - only true up to 'saturation' point - adding substrate after all active sites are full has no effect - substrate con decreases with time so if no other variables change then rate will decrease which makes initial rate the highest rate of reaction

Answer 117

- measure how fast product appears (easy to collect oxygen and how fast its given off) - OR measure disappearance of a substrate rather than appearance of product and use this to compare rate under different conditions

Answer 118

1. set up boiling tubes with same volume & conc of hydrogen peroxide, to keep pH constant add same amount of buffer solution to each tube 2. set up apparatus to measure volume of oxygen produces from each boiling tube 3. put each tube in water bath at different set temps along with another tube containing catalase 4. use pipette to add same volume and conc of catalase to each tube 5. record how much oxygen is produced in first min (stopwatch) 6. repeat 3 times & find mean 7. calculate mean rate of reaction at each temp (oxygen produced/time)

Answer 119

- non-protein substance bound to an enzyme - inorganic molecules or ions that help bind enzyme and substrate - arent directly involved in reaction so arent used up or changed - e.g. chloride ions are cofactors for amylase

Answer 120

- type of organic cofactor - participate in reaction and are changed (like a second substrate) - act as carriers, moving chemical groups between enzymes - continually recycled

Answer 121

- a cofactor that's tightly bound to enzyme - e.g zinc ions area prosthetic group for carbonic anhydrase and are a permanent part of the enzyme

Answer 122

- competitive inhibitors have similar shape to substrate - they compete with substrate to bind to active site but no reaction takes place - block active site - how much the enzyme is inhibited depends on conc of inhibitor and substrate - high conc of inhibitor = takes up nearly all active sites - high conc of substrates = chance of substrate getting active site before inhibitor increases - increasing conc of substrate increases rate

Answer 123

- non-competitive inhibitors bind to enzyme away from active site (bind to allosteric site) - causes active site to change shape - dont compete with substrate molecules - increasing conc of substrate wont affect rate of reaction

Answer 124

if they're weaker hydrogen bonds or weak ionic bonds, inhibitor can be removed

Answer 125

if they're strong, covalent bonds, inhibitor cant be removed easily

Answer 126

1. antiviral drugs e.g. reverse transcriptase inhibitors, reverse transcriptase catalyses replication of viral DNA 2. some antibiotics e.g. penicillin inhibits transpeptidase which catalyses formation of proteins in bacterial cell walls. this weakens cell wall and prevents bacterium regulating its osmotic pressure and is killed

Answer 127

- cyanide, irreversible inhibitor of cytochrome c and inhibits cell respiration so cells die - malonate, inhibits succinate dehydrogenase - arsenic, inhibits action of pyruvate dehydrogenase which catalyses respiration reactions

Answer 128

end-product inhibition

Answer 129

- series of connected metabolic reactions - the product of first reaction takes part in second reaction and so on - each reaction is catalysed by a different enzyme

Answer 130

- when the final product in a metabolic pathway inhibits enzyme that acts on earlier pathway - controls and regulates amount of end product - product and end-product inhibition is reversible so when product levels drop, level of inhibition falls so enzyme can function again

Answer 131

- enzymes are sometimes synthesised as inactive precursors in metabolic pathways to prevent them causing damage to cells - part of precursor molecule inhibits its action as an enzyme

Answer 132

control what passes through them

Answer 133

- are a barrier to cell and its environment, controlling which substances enter and leave cell - partially permeable - substances move across through diffusion, active transport and osmosis - allow recognition by other cells - allow cell communication/cell signalling

Answer 134

- membranes around organelles divide cell into components - act as a barrier between organelle and cytoplasm - can form vesicles to transport substances between different areas of the cell - control which substances enter and leave the organelle - membranes within organelles act as barriers between membrane and contents - sit of chemical reactions

Answer 135

- describes arrangement of molecules in a membrane - phospholipid bilayer model - bilayer is fluid because phospholipids are constantly moving - cholesterol and protein molecules are present - some proteins have polysaccharide chain attached (glycoproteins) - some lipids have a polysaccharide chain attached (glycolipids)

Answer 136

- have a hydrophilic head and hydrophobic tail - heads face out, tails face in - centre of bilayer is hydrophobic so membrane doesnt allow water-soluble substances through it

Answer 137

- type of lipid - present in all but bacterial membranes - fit between phosohplipid molecules and bind to hydrophobic tails so they pack closer (membrane goes less fluid) - at low temp cholesterol prevents phospholipids packing too close so increases fluidity

Answer 138

- some form channels in the protein that allow small or charged particles through - other proteins transport molecules & ions across membrane by active transport and facilitated diffusion - also act as receptors for molecules in cell signalling

Answer 139

- they stabilise membrane by forming hydrogen bonds with water molecules - sites where drugs, hormones and antibodies bind - are antigens

Answer 140

how cells communicate

Answer 141

using messenger molecules: - one cell releases messenger molecule - molecule travels to another cell - messenger molecule is detected by the cell as it binds to a receptor on its cell membrane

Answer 142

- proteins in cell membrane act as receptors for membrane molecules - receptor proteins have specific shaped (only messenger molecules with complementary shape can bind) - different cells have different types of receptors - they respond to different messenger molecules (cell that responds is a target cells)

Answer 143

1. cut 5 equal size pieces of beetroot and rinse to remove any pigment released 2. place pieces in test tubes with 5cm3 of water 3. place each tube in water baths of different temps 4. remove pieces of beetroot leaving coloured liquid 5. use colorimeter - higher permeability = more pigment released = higher absorbance of liquid

Answer 144

- increasing temperature increases membrane permeability - temps below 0°C: low energy so low movement, packed closely, membrane is rigid - temps between 0 and 45°C: phospholipids can move & arent packed as tight, membrane is partially permeable, as temp increases bilayer moves more - increases permeability - temps above 45°C: bilayer starts to melt, becomes more permeable, water inside cell expands, channel & carrier proteins deform so cant control what enters and leaves so increases permeability

Answer 145

- surrounding cells in solvent increases permeability of membranes - due to solvents dissolving lipids so membrane loses structure - different solvents increase permeability differently - increasing conc of solvent increases permeability

Answer 146

- net movement of particles from high to low conc (down gradient) - molecules diffuse both ways but net movement is only to low conc - diffusion is passive - no energy needed

Answer 147

- able to diffuse easily though spaces between phospholipids (e.g. H2O & CO2) - water is small enough to fit between phospholipids so can diffuse across plasma membranes (diffusion of water molecules like this is osmosis)

Answer 148

1. concentration gradient - higher = faster 2. thickness of exchange surface - thinner = faster 3. SA - larger = faster 4. temperature - warmer = faster (kinetic energy)

Answer 149

- cut agar jelly into different sized cubes & work out their SA:V - time how long it takes each cube to go colourless when placed in same conc of HCl - expect larger SA:V to go colourless fastest

Answer 150

- prepare test tubes containing different concentrations of HCl - put equal sized cubes of agar jelly in each test tube and measure time taken to go colourless - expect highest conc to be fastest

Answer 151

- prepare many boiling tubes containing same conc of HCl and put tubes in varying temps - put equal sized agar jelly in each boiling tube and measure time taken to go colourless - expected higher temp to be fastest

Answer 152

1. used by some larger molecules, polar molecules and ions 2. moves particles down a conc gradient 3. passive process

Answer 153

- carrier proteins move large molecules into/out of the cell - different carrier proteins facilitate diffusion of different molecules 1. larger molecule attached to carrier protein 2. protein changes shape 3. releases molecule on opposite side of membrane OO\/OO to OO/\OO

Answer 154

- channel proteins form pores in membrane for charged particles to diffuse through down conc gradient - different channel proteins facilitate diffusion of different charged particles OOOI IOOO

Answer 155

active transport (same process as facilitated diffusion but ATP is used (active process) to move substance against gradient)

Answer 156

endocytosis

Answer 157

- a cell surrounds a substance within a section of plasma membrane - membrane pinches off to form a vesicle containing ingested substance (endocytosis) - some cells take in much larger objects by endocytosis e.g. WBCs - active process

Answer 158

exocytosis

Answer 159

- some substances produced by the cell need to be released (exocytosis) - vesicles containing these substances pinch off from sacs of Golgi and move towards plasma membrane - vesicles fuse with plasma membrane and release contents outside cell - some substances are inserted striaght into plasma membrane - active process

Answer 160

- diffusion of water molecules across a partially permeable membrane down a WP gradient - molecules from high WP go to low WP

Answer 161

likelihood of water molecules to diffuse out of or into a solution

Answer 162

net movement of molecules is into the cell - cell bursts

Answer 163

water molecules pass into and out of cell equally - cell stays the same

Answer 164

net movement of water molecules is out the cell - cell shrinks

Answer 165

- net movement of water is into cell - vacuole swells - and cytoplasm push against the cell wall so cell becomes turgid

Answer 166

water moves into and out of cell equally - cell stays the same

Answer 167

- net movement of water is out the cell - cell becomes flaccid (limp) - cytoplasm and membrane pull away from cell wall - plasmolysis

Answer 168

1. prepare sucrose solution of 0.0, 0.2, 0.4, 0.6, 0.8 1.0 M concentrations 2. use cork borer to cut potatoes into same sized pieces 3. divide into groups of 3 and measure mass ot each group 4. place one group in each solution 5. leave chips for as long as possible (same amount of time) 6. remove chips & dry with towel 7. weigh each group and record results 8. calculate % change in mass 9. plot results on graph

Answer 169

1. starts when a cell has been produced by cell division, ends with cell dividing to produce 2 identical cells 2. consists of cell growth & DNA replication (interphase) & cell division (M phase - mitosis & cytokinesis) 3. interphase is divided into G1, S and G2 4, cell cycle is regulated by checkpoints to check process can continue

Answer 170

cell grows and new organelles and proteins are made

Answer 171

cell checks that the chemicals needed for replication are present any damage to DNA before S-phase

Answer 172

cell replicates its DNA ready to divide by mitosis

Answer 173

cell keeps growing and proteins needed for cell division are made

Answer 174

cell checks whether all DNA has been replicated without damage - cell then enters mitosis

Answer 175

1. gap phase 1 2. G1 checkpoint 3. synthesis 4. gap phase 2 5. G2 checkpoint (then goes to mitosis and cytokinesis)

Answer 176

- growth of multicellular organisms and repairing damaged tissues - also a method of asexual reproduction for some plants, animals and fungi

Answer 177

- cell carries out normal functions - cells DNA is unravelled and replicated to double its genetic content - organelles are also replicated - ATP content is increased

Answer 178

- chromosomes condense getting shorter and fatter - centrioles start moving to opposite ends of the cell forming spindle fibres - nuclear envelope breaks down and chromosomes lie free in cytoplasm

Answer 179

- chromosomes line up along middle of cell and become attached to spindle by their centromere - at metaphase checkpoint cell checks chromosomes are attached to spindle before mitosis continues

Answer 180

- centromeres divide, separating sister chromatids - spindles contract pulling chromatids to opposite ends of the cell

Answer 181

- chromatids reach opposite poles on spindle - uncoil and become long and thin, now called chromosomes again - nuclear envelopeforms around each group of chromosomes (so now 2 nuclei)

Answer 182

- cytoplasm divides - animal cells: cleavage furrow forms to divide cell membrane - now there are 2 genetically identical daughter cells - separate process to mitosis

Answer 183

by staining chromosomes to view under a microscope

Answer 184

- is a type of cell division that happens in reproductive organs to produce gametes - in sexual reproduction, 2 gametes join together at fertilisation to form a zygote - involves reduction division - cells formed by meiosis are genetically different - they end up with different combination of chromosomes

Answer 185

- cells that divide by meiosis have a full number of chromosomes - cells that form from meiosis have half the number of chromosomes (haploid)

Answer 186

reduction division

Answer 187

- chromoeomes condense - chromosomes arrange into homologous pairs and crossing over occurs - centrioles start moving to opposite ends of the cell forming spindle fibres - nuclear envelope breaks down

Answer 188

homologous pairs line up across centre of cells and attach to spindle fibres by their centromeres

Answer 189

- spindles contract, separating homologous pairs - one chromosome goes to each end of the cell

Answer 190

nuclear envelope forms around each group of chromosomes

Answer 191

2 haploid daughter cells are produced

Answer 192

- the 2 daughter cells undergo prophase II, metaphase II, telophase II and cytokinesis (stages very similar to stages in mitosis) - in anaphase II, pairs of sister chromatids are separated so each new daughter cell inherits one chromatid from each chromosomes - 4 haploid daughter cells are produced (gametes)

Answer 193

- chromatids twist around each other and bits of the chromatids swap over - chromatids still contain the same genes but now have different combination of alleles

Answer 194

- each homologous pair of chromosomes is made from one maternal and one paternal chromosome - when homologous pairs line up in metaphase I and are separated in anaphase I, its random which chromosome ends up with which daughter cell - so 4 daughter cells have different combinations of maternal and paternal chromosomes - leads to genetic variation

Answer 195

unspecialised cells

Answer 196

- stem cells divide to become new cells which become specialised - in animals stem cells can replace damaged cells - plants are always growing so stem cells are used for new roots and shoots - stem cells (in meristems) can differentiate into xylem and phloem - can divide and produce more undifferentiated cells

Answer 197

stem cells in the vascular cambium

Answer 198

- defend body against diseases - flexible shape allows them to engulf foreign particles or pathogens - have many lysosomes in their cytoplasm that contain digestive enzymes to break down engulfed particles

Answer 199

- carry oxygen in the blood - biconcave disc shape = large SA for gas exchange - have no nucleus so theres more room for haemoglobin

Answer 200

- cover surfaces of organs - joined by interlinking cell membranes - ciliated epithelia have cilia that beat to move particles away - squamous epithelia are very thin to allow efficient gas exchange

Answer 201

- have flagellum so can swim to egg - have many mitochondria to provide energy to swim - acrosome contains digestive enzymes to penetrate surface of egg

Answer 202

- do most of photosynthesis - have many chloroplasts so can absorb lots of sunlight - thin cell walls so CO2 can easily diffuse into the cell

Answer 203

- absorb water and mineral ions from the soil - large SA for absorption - thin , permeable cell wall for entry of water and ions - have extra mitochondria to provide energy needed for active transport

Answer 204

- found in pairs with a gap between to form stroma - in light, they take up water and become turgid - thin outer walls and thickened inner walls forces them to bend outwards - opening stomata - allows leaf to exchange gases for photosynthesis

Answer 205

a group of cells (can be multiple types) specialised to work together to carry out a particular function

Answer 206

- single layer of flat cells lining a surface - found in many places incl. alveoli in lungs

Answer 207

- layer of cells coveres in cilia - found on surfaces when things need to be moved

Answer 208

- made of bundles of muscle fibres - 3 types of muscle tissue: cardiac, smooth, skeletal

Answer 209

- type of connective tissue found in joints - shaped and supports ears, nose and windpipe - formed when cells secrete extracellular martix which they become trapped inside

Answer 210

- plant tissue that transports water and supports plant - contains hollow xylem vessel cells (dead) and parenchyma (living)

Answer 211

- transports sugars around the plant - arranged in tubes and made of sieve tube elements and companion cells - sieve cell end walls (sieve plates) have holes in so sap easily moves through

Answer 212

group of different tissues that work together to perform a particular function

Answer 213

cells, tissues, organs, organ systems, organism

Answer 214

- squamous epithelial tissue - ciliated epithelial tissue - elastic connective tissue - vascular tissue

Answer 215

- palisade tissue - epidermal tissue - xylem tissue - phloem tissue

Answer 216

- made up of all organs, tissues and cells involved in breathing - trachea, larynx, nose, mouth, diaphragm

Answer 217

- made up of all organs involved in blood supply - heart, arteries, veins and capillaries

BIOLOGY MODULE 2 (papers 1,2, & 3) Flashcards

cell structure, biological molecules, nucleotides and nucleic acids, enzymes, biological membranes, cell division and cellular organisation