biology unit 2

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what is the difference between interspecific and intraspecific
interspecific is where one species differes from another whereas intraspecific is where the same species differ
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causes of variation
genetic differences, environmental influences (mutations, meiosis, fusion of gametes)
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standard deviation
difference of mean divided by sample size
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what does DNA stand for and what is it made up of
deoxyribonucleic acid. made up of sugar called deoxyribose, a phosphate group and paired bases
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What bond joins the 2 strands of nucleotides in DNA
hydrogen bonds
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what number of hydrogen bonds does each paired base have
A and T have 2 hygrongen bonds C and G have 3
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how is DNA adapted to cary out functions
stable to withstand high temps. 2 seperate strands which can seperate for DNA replication and synthesis
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what is RNA
single stranded, has bases C G A and U (urical) and bonded by disulfied bonds
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what is a gene
a section of DNA that code for the manufacture of proteins
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what is the triplet code
It's the sequence of three nucleotides that codes for the synthesis of a specific amino acid
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where are chromosomes found and what are they made up of
found in eukaryotik cells, made up of 2 chromatid and a centrometre
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why do humans have an equal number of chromosomes (46)
because they occur in pairs clled homologus pairs
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what is a homologus pair
2 chromosomes that deterimine the same genetic characteristic
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what is an allele
a gene exists in 2 or more forms, each of these forms is an allelle from each parent
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what is meiosis
from sexual reproduction, produces 4 daughter nuclei with half the number of chromosomes
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what is mitosis
for growth and repair, forms 2 daughter nuclei with the same number of chromosomes
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what is the process of meiosis
in sex reproduction 2 sex gametes fuse together, and chromatids wrape around eachother, pair splits up and each goes into diff daughter cell, then chromatids move apart and form 4 daughter cells
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what is independant segregation
is meiosis chromosome lines up with homologus partner randomly, when passing to daughter cell it is random
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what is genetic recombination by crossing over
when homologus pairs like up chromatids become twisted around one another, sometimes chromatids break off and rejoin with homologus partners, this is called rocombination
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what does diploid and haploid mean
diploid has the same number of chromosomes haploid has half the number of chromosomes
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what is genetic diversity
the genetic differences of individuals within a population, the amount of different allelles a species has
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selective breeding
identifying individuals with the desired characteristics and using them for the next generation
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the founder effect
when a few individuals rom a population colonise a new region
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genetic bottlenecks
when a population suffers from a dramatic drop in pop meaning survivors have fewer allelles
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what is haemoglobin
a group of protein molecules with a quaternary structure, contains a HAEM group which contains ions to combine with ocygen
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what is the role of haemoglobin
to transport oxygen around the body, readily associate with oxygen and readily disociate with oxygen and tissues which require it
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hameoglobin
can have a high affinity for oxygen (take up easily) or a loew affinity for oxygen (take up less easily)
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loading, transport and unloading of oxygen
the higher the rate of respiration- the mor co2 tissues produce- the lower the ph- the greater the haemoglobin shape change- rhe more readily oxygen is unloaded- the more oxygen available for respiration
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oxygen dissociation curve
the furthur the curve to the left the greater the affinity for oxygen the furthur to the right the lower the affinity for oxygen
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what is starch
polysacharride found in many parts of a plant, made up of chains of alpha glucos, linked by glycosidic bonds
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how is starch adapted for storage
it is insoluble so doesnt diffuse easily, it is compact so can fit alot in a small space, when hydolysed forms alpha glucose for respiration
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what is glycogen
similar to starch however found in animals and has shorter chains, major carbohydrate storage for animals
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what is cellulose
differs as it is made up of beta-glucose, made of straight chains instead of coiled so hydrogen bonds form across chains, grouped together to form microfibrils which make fibres
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what does cellulose do
provides sterdiness to plant, stops plant from bursting due to osmosis
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structure of a blood vessel
tough outer layer (resist pressure changes) muscle layer (control blood flow) alastic layer (maintain blood pressure) endothelium (diffusion) lumen (central blood vessel)
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what is tissue fluid
fluid qhere substances are exchange between blood and cells
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formation of tissue fluiid
blood is pumped around body it reaches cappilerries creating hydorstatic pressure, this forces tissue fluid out of the blood plasma howver only small molecules as pressure isnt big enough, cells and proteins left in blood (ultrafiltration)
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return of tissue fluid to circulatory system
once exchanged materials must be returned. hydrostatic pressure in cappilaries is reduced so tissue fluid is forced back in by pressure, also from osmosis as water potential is greated in cappileries due to proteins
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return of tissue fluid continued
not all can return via this way, some returns via lymphatic system moved by hydrostatic pressure and contraction of muscles
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what doe chloroplasts do
carry out photosynthesis in plants
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what makes up a chloroplast
the grana- stacks of thykaloids (disk like structures) which contains chlorophyll. The stroma- fluid filled matrix
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how are chloroplasts adapated for photosynthesis
grana provides a larage surface area for attachment of chlorophyll and enzymes which carry out phtosynthesis. Stroma posseses enzymes needed for photo. contain DNA for synthesis of proteins needed
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what 2 ways does cell division occure
cell dicision and nucleur division
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semi- conservative replication
enzyme dna helicase breaks up hydrogen bondslinking the base pairs, double helix seprates, complimentary nucletides are attracted where enegry is used to activate them and joined together by DNA polymerase
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what are the stages of mitosis
phrphase (primary) metaphase (middle) anaphase (apart) telephase (two cells)
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what is interphase
occupies most of cell cycle, known as resting phase where no division takes place
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cell differentation
when organisms are adapted in different ways to perform a partiular role
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what is a tissue
a collection of similar cells that perform a specific function
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what is an organ
a combination of tissues which work together to perform a variety of functions eg stomach
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how are organsims adapted for efficient diffusion
flat bodys so cells arnt far from surface or specialised organs eg lungs
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gas exchange in insects
have to conserve water but also exchange gases, have waterproof coverings, small surface area to vol ratio
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gas exchange in insects
they have internal network of tubes called tracheao which divude into smaller tubes called tracheoles. takes oxygen directly to tisses
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how do gases enter and leave tracheae
through spiricles which are opened and closed by a valve
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what are gills made up of
gill filaments stacked like a book and on these are gill lamalae which increase surface area
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what is the countercurrent flow
where the flow of water over lamallae and the flow of blood within filament is opposite. so diffusion of oxygen from water can go into blood fast
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structure of a leaf
thin flat shape which provideslarge surface area, lots of stomata, interconnceting air spaces
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what are stomata
pores which mainly occur on the lower eppidermis surrounded by gaurd cells which open and close stomata to reduce evaporation.
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what do mammals have for efficent diffusion
double circulatory system (blood passes twice through heart for each complete circuit)
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movemenbt of water through plants
water is taken up by root hairs by osmosis due to soil having high WP and root hairs low.
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What are the 2 pathways within a plant
Apoplastic pathway- water travels through the cell walls, The synplastic pathway- takes place in the cytoplasm of cells across the cortex of the plant
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what does the casparian ***** do
within the endodermis, prevents water from the apoplastic pathway moveing any furthur due to a waterproof band, forced into protoplast of endodermis
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how does water enter the exylem
due to active transport, salts lower the water potential so water can then move in by osmosis
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how does water move up the xylem
Root pressure, Also when water moves out of stomata replaced by water from xylem called cohesion-tension
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what is cohesion-tension
water evaporates from leaves due to transpiration, water molecules form hydrogen bonds between them forming continuous pathway, when water avaporates water drawn up as a result of cohesion .
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factors affecting transpiration
light-photosynthesis only occurs in light stomata open more water lost, temp- rise in temp increase KE meaning water moves faster, humidity- no of water in air, air movement
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what are xerophytic plants
adapted to living in areas where water loss may exceed water uptake
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how are xerophytik plants adpated
a thick waxy cuticle, rolling up of leaves, hairy leaves, stomata in pits or grooves, reduced SA to vol ratio
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what is taxonomy
groups and their positions in the heirachal order
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what is the heirachal order
Kingdom, phylum, class, order, family, genus, species (keepign pants clean often favours good sex)
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what is DNA hybridisation
DNA from 2 species exctrated, one labelled and mixed with other, DNA heated to seperate strands, cooled to allow strands to recombine with complimetary bases makes hybrid strands
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if strands have to be seprated by a high temp in hybridisation what does it mean
2 species are closesly related as lots of compliemtray bases and hydrogen bonds
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what is immunological comparisons of proteins
the process that antibodies will respond to specific anitgens. Greater number of similar antigens the more similar
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what is courtship behaviour
bahviour in species which helps to- recognise members of own species, identify a mate capable of breeding
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what is a mutation
a change in the structure of DNA which changes the amino acid sequence which could make a new protein
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what is conjugation
the transfer of one bacterial cell to another
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how does conjugation work
a cell produces a thin projection which which meets another cell forming a conjugation tube. Donor cell replicates DNA and passes to other cell which is made linear, cell now has new characteristics from donor cell.
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what is horizontal gene transmission
where genes are [assed rom one species to another
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what is horizontal gene transmission
where genes ae passed down from 1 generation to another
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what are antibiotics
substances produced by living organisms which destroy or inhibit the grown of microorganisms produces by fungi or bacteria
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how do antibiotics work
prevent bacteria making normal cell walls so they burst due to osmotic lysis. inhibit the synthesis of peptide cross linkages in cell walls
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antibiotic resistance
due to mutations therefore a change in protein. The new protein enzyme is able to break down the antibiotic before able to kill bacteria.
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tb and aintibiotic resistance
course has to be take for 6-9 months but when patients feel better they stop taking them, resistant strains remain and grow and divide so now multiple antibitic resistant strains of TB
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Other cards in this set

Card 2

Front

causes of variation

Back

genetic differences, environmental influences (mutations, meiosis, fusion of gametes)

Card 3

Front

standard deviation

Back

Preview of the front of card 3

Card 4

Front

what does DNA stand for and what is it made up of

Back

Preview of the front of card 4

Card 5

Front

What bond joins the 2 strands of nucleotides in DNA

Back

Preview of the front of card 5
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