monomer +polymers of...
1) carbohydrates
2) proteins
3) nucleic acids
carbohydrate= monosaccharide, polysaccharid
proteins= amino acids, polypeptide
nucleic acid= nucleotides, DNA/RNA
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properties of water
1|) liquid at room temp- provide habitats
2) density- ice is less dense than water
3) solvent- transportation of molecules
4)cohesion/surface tension- insects can walk on water
5) high SHC- stable environment
6) high latent heat for vaporisation- sweat to
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structure + functions of carbohydrates
structure- C, H, O and glycosidic bonds formed between 2 monosaccharides via hydrolysis
1) source of energy (glucose)
2) store of energy (starch+glycogen)
3) structural units (cellulose in plants)
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monosaccharides + hexose, pentose and triose sugars
monosaccharides= simplest carbohydrate
soluble in water
large no. carbon-hydrogen bonds
hexose= 6 carbon atoms- glucose- ring/cyclic form
pentose= 5 carbon atoms- ribose- ring/cyclic form
triose=3 carbon atoms- straight chains
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made when 2 monosaccharides are joined together
Aglucose+Aglucose= maltose
Aglucose+fructose= sucrose
Bglucose+Aglucose= lactose
Bglucose+Bglucose= cellobiose
condensation reaction ,', glycosidic bond formed + produces water
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why are polysaccharides good energy stores
polysaccharide= polymers of monosaccharides
1)glycogen+starch compact- less space taken
2)contain glucose molecules- can be broken down (hydrolysis) for respiration
3)less soluble in water= doesnt effect water potential
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types of polysaccharides + their structure
amylose (plants)= long chain of glycosidic bonds 1-4, coils into spiral shape (h bonds), hydroxyl group on inside (lowers solubility)
amylopectin (plants)= glycosidic bonds 1-4, branches formed from 1-6 glycosidic bonds, spiral shape
glycogen (animals)= g
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cellulose as a structural unit
found in cell walls
tough, insoluble and fibrous
long chains of Bglucose via condensation reaction
straight chains, every other one is rotated 180*
difficult to digest
macrofibrils+microfibrils have high tensile strength
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structure + function of triglycerides
triglycerides= made up of glycerol and fatty acids
saturated- no C=C bonds
unsaturated- C=C bonds ,', fewer H
branched due to kinks in the chain
1) energy source
2)energy store
3) insulation
4) protection
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structure + function of phospholipids
phospholipids= made up of a glycerol molecule, 2 fatty acid chains and a phosphate group
one chain is saturated, the other is unsaturated
make up the phospholipid bilayer= hydrophilic phosphate heads point out + hydrophobic fatty acid tails point inward
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structure of amino acids
amino acid= made up of 4 elements- carbon, hydrogen, oxygen and nitrogen
amino group, R group + carboxyl group
joined together by covalent peptide bonds
can act as buffers by resisting large changes in pH
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structure sequence of proteins
1) primary= sequence of amino acids found within a molecule
2) secondary= coiling/folding due to hydrogen bonds ,', forms beta pleated sheets
3) tertiary= ionic+disulphide bonds, spherical (globular), supercoiled (fibrous)
4) quaternary= multiple poly
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types of bonds
hydrogen= between H and negative atoms, hydroxyl+carboxyl groups, tertiary+quaternary protein structure
ionic= between carboxyl+amino groups, ionise into NH3*+COO-
disulphide link= between R groups of 2 cysteines, strong covalent bonds
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globular proteins
globular= spherical in shape + soluble in water
1) haemoglobin- 4 polypeptide chains, have a prosthetic group (iron in each of the 4 ahem groups)
2) insulin- 2 polypeptide chains (A chain- alpha helix + B chain- beta pleated sheets)
3) insulin
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fibrous proteins
fribrous= long + thin in structure, soluble in water
1) collagen- mechanical strength, tendons, cartilage, artery walls
2) elastin- cross-linking + coiling makes it extensible, skin, lungs, bladder
3) keratin- many disulphide bridges+hydrogen bonds, very
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inorganic ions
(cations + anions)
cations (+)
1) sodium- osmotic pressure, muscle contraction
2) hydrogen- photosynthesis
3) calcium- teeth, membrane impermeability
4) potassium- active transport, water+pH levels
anions (-)
1) phosphate- phospholipids, plant root growth
2)chloride- urine
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structure + functions of nucleotides
structure= 5 carbon sugar, phosphate and nitrogenous base (A+T,G+C)
2 anti-parallel polynucleotide strands
covalent bonds between sugar+phosphate
phosphodiester bonds between polynucleotides
1) components of coenzymes
2) form monomers of nuclei
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hydrogen bonds in the bases
Adenine+Thymine= 2 hydrogen bonds
Guanine+Cytosine= 3 hydrogen bonds

purine molecules- 2 rings (Adenine+Guanine)
pyrimidine molecules- 1 ring (Thymine+Cytosine)

pyrimidine always pairs with purine to give equal sized rings on the DNA ladder
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anti-parallel sugar (phosphate backbones)
opposite directions of the strands based on the opposite directions of the 3rd+5th carbon molecules
5'end= phosphate group @ to 5th carbon on deoxyribose sugar
3'end= phosphate group @ 3rd carbon on deoxyribose sugar
complimentary base pairing joined by
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DNA in eukaryotes vs prokaryotes
1) DNA in nucleus
2) tightly wound around histones into chromosomes
3) loop of DNA without histones in mitochondria+chloroplasts
1) DNA loop within cytoplasms
2) not enclosed in nucleus
3) 'naked'- not wound round histones
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stages of DNA replication
during interphase, semi conservative (one old strand, one new strand)
1) DNA unwinds- double helix untwists via gyrase
2) hydrogen bonds between bases break via helicase
3) free phosphorylated nucleotides bind to exposed bases
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stages of DNA replication
4) polymerase catalyses addition of new nucleotide baseline 5'-3' direction, uses one strand as template
5) leading strand catalysed continuously, lagging strand in fragments to be joined via ligase
6) hydrolysis of activated nucleotides to release extra
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stages of transcription- synthesis of polypeptides
making mRNA from DNA template
1) gene unwinds + unzips
2) hydrogen bonds between bases break
3) RNA polymerase catalyses temporary hydrogen bonds between RNA nucleotides + their bases- only on one DNA strand (template)
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stages of transcription
4) a length of RNA complimentary to template strand of the gene is produced ,', other strand is the coding strand
5) mRNA passes out of the nucleus and @ to a ribosome
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stages of translation
formation of proteins at the ribosomes
1) tRNA made in nucleus
2) tRNA bring amino acid + find their place when anti-codon binds to complimentary codon via H bonds on mRNA
3) ribosome moves along mRNA and reads code
4)amino acid sequence determined by b
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genetic code
1) degenerate- reduces effect of mutations
2) universal
3) non-overlapping- read from a fixed point
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code for polypeptides
1) sugar molecule is ribose
2) nitrogenous base is uracil (replaces thymine)
3) single-stranded polynucleotide
4)3 forms- messenger, transfer, ribosomal
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specialised animal tissue
1) epithelial- covers/lines free surfaces in the body (skin, blood vessels, organ walls)
2) connective- tendons, ligaments
3) cartilage- hyaline (embryonic skeleton), elastic (outer ear), fibrous (discs between vertebrae)
4) muscle- skeletal (movement),
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specialised plant tissues
1) epidermal- protective covering (waxy cuticle)
2) vascular- carry water/minerals + photosynthesis products (xylem+phloem)
3) meristematic- contains stem cells (roots + shoots)
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animal organs
organ= collection of tissues working together to complete the same function (heart,brain,stomach)
organ systems= number of organs working together to carry out an overall life function
circulatory- heart+blood vessels- transport to and from cells
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plant organs
stem- support, transportation, storage
flower- sexual reproduction
leaf- photosynthesis
root- mineral+water absorption, storage, anchorage
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sources of stem cells
induces pluripotent cells= reprogramming differentiated cells to switch on key genes to become undifferentiated
adult stem cells= muscle, bone, tissue, skin- renewing source for undifferentiated cells
embryonic= early embryo when a zygote starts to divide
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uses of stem cells
1) bone marrow transplants- treat diseases in the blood
2) repair of damaged tissues- hepatocytes to treat liver disease, nerve tissue to repair spinal injuries, treat mice with type 1 diabetes by programming IPS cells to become pancreatic beta cells
3) d
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equation for photosynthesis
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reactants, products + purpose of respiration and photosynthesis
respiration- glucose/oxygen, CO2/H2O, release energy
photosynthesis- CO2/H2O, glucose/oxygen, store energy
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what's the compensation point + compensation period
compensation point- when photosynthesis and respiration occurs at the same rate (no gain/loss of carbs)
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what type of reaction is photosynthesis
-carbon fixation so electrons required
-addition of electrons is a reduction reaction
-helps regulate concentration of CO2 in the atmosphere
-endothermic so requires energy
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photosynthetic pigments- chlorophyll
found within the plasma membrane
mixture of pigments chlorophyll a + chlorophyll b
chlorophyll a= 2 forms- P680+P700
primary pigments in primary reaction centre
chlorophyll b= accessory pigments
(carotenoids+ xanthophyll)
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light dependent stage of photosynthesis
involves direct use of sunlight energy
1) light harvesting at the photosystems
2) photolysis of water
3) photophosphorylation- ATP production
4) formation of reduced NAD
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2 types of photosystem
PSI= the pigment at primary reaction centre is chlorophyll a (P700), peak absorption of red light at a wavelength of 700nm
PSII= the pigment at primary reaction centre is chlorophyll a (P680), peak absorption of red light at a wavelength of 680nm
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role of water
-source of protons (hydrogen ions) to be used in photophosphorylation
-donates electrons to chlorophyll to replace those lost when light strikes chlorophyll
-is the source of by-product oxygen
-keeps plant cells turgid, enabling them to function
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types of photophosphorylation
non-cyclic photophosphorylation- involves both PSI + PSII, produces ATP, oxygen + reduced NADP
cyclic photophosphorylation- involves only PSI, produces ATP in smaller amounts
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non-cyclic photophosphorylation
1) photon of light strikes PSII the energy is channeled to the primary pigment reaction centre
2) energy excites a pair of electrons inside chlorophyll
3) electrons escape from chlorophyll + captured by an electron carrier
4) electrons replaced by electr
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Card 2


properties of water


1|) liquid at room temp- provide habitats
2) density- ice is less dense than water
3) solvent- transportation of molecules
4)cohesion/surface tension- insects can walk on water
5) high SHC- stable environment
6) high latent heat for vaporisation- sweat to

Card 3


structure + functions of carbohydrates


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Card 4


monosaccharides + hexose, pentose and triose sugars


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