genetics Flashcards
what does sexual reprodcution require
fertillisation and 2 parents
what is fertillisation
the fusion of male and femake gametes
how mnay chromomes do gametes have
23
what process does sexual reproduction happen by
meiosis
do plants undergo sexual reproduction or asexula reproduction
both
why is there gentic variation in seuxal reproduction
the offspring has half the femeale chromomes and half the male chomomesom
do animals undergo sexual or asexual reproduction
sexual
what does asexual reproduction require
one parent
why is there no genetic variation in asexual reproduction
the offspriig is going to be geneetically identical and no mixing of genetic infor
do eukaryotes undergo asexual or sexual reproduction
asexula
do eukaryotes undergo mitosis or binary fusion
mitsosis - two idnetical cells formed from one
what process are gametes formed by
meiosis
do bacteria undergo binary fusion or mitosis
binary fusion
do bacteria reproduce asexaully or sexually
asexually
what are the pros of asexual reproduction
1.only requires one parent
2. quick and easy
what are the cons of asexaul reproduction
- more suceptile to disease - if one offspring gets it the rest will have it because they are gentically idnetical
- no genetic variation
- can’t adapt to conditions
what are cons of sexual reproduction
- sexual reproduction requires 2
- time consuming
what are pros of sexaul reproduction
- less suceptiple to disease because there is genetic variation
- can adapted to condions like climate change
haploid
half the chromomes
diploid
full amount of chromomes
how much is an haploid cell
23
how much is in a diploid cell
46
how many gametes are there after meiosis
4, that are not gentically idenitcal
why are the gametes produced after meiosis not gentically identiccal
chromomesomse shifted, resulting in random chromosomes in each cell
what happens after meiosis
- gametes fertilise to produce a cell with 4 chromsomes
- the cell will undergo mitsosi
- embryo will form
- diffrentiation will take place
what is a gamete
a cell with half the number of chromosomes of the parent
what are clones
offspring that are gentically identical
what is reduction division
when the number of chromosomes in gametes halves
what is DNA
a polymer made from 2 strands ehich cooil around each other
what are nucleotides
repeating unit in DNA and RNA that consist of sugar, a phosphate group and a base
what are complementary base pairings
when one of the four bases in DNA pair with another four bases
what is a genome
found in the cells nucleus and contains the full dna of an organism
what is a gene
small part on a chromosome
what is a codon
a sequence of three bases that is that code for a particular amino acid
what is a population
the number of one specieis in a habitat
what is an allele
diffrent forms that each gene has
does dna have a double or single helix
double helix
what are the two main stages of protein synthesis called
transcription and translation
where is the nucleoid found
dna
what is variation
it means that the individual in a popilation show difference in characteristics
what is discontinous variation
when there is a limited number of values that a limited number of values that an individual can possess
why is dna a polymer
it is made of many nucleotides joined in a chain
in organisms all the cells that have a nucleus will have a complete set of chromomes, gametes as an exception to this. what does this mean
thar cells contain every gene required to create every protein the organism will ever need
how many main stages are there in protein synthesis
2
what is the genegttic matriel in the nucleus of cells made from
dna `
what happens during tranlsattion
- the strand of mRNA travels out of the nucleus
- in the cytoplasm, a ribosome attactches to the mRNA strand
- A tRNA molecule pair with each codon
the ribsomes joins together the amino acids carried by the tRNA molecules - this results in the formation of a polyppeptice
- the types and order of amino acids in the chain cause it to fold into a specific shape
what happens during transcription
- inside the nucleus RNA polymerase attactches to a non coding section of dna
- the enzyme, rna polymerase seperate the two strands of DNA
- rna polymerase continues to move along the dna to reach the coding region of a gene
- rna polymerase adds complementary rna nucleotides to the template strand
- rna polymerase links the rna nucletiddes together to form a strand of mRNA
what does dna stand for
deoxyribonucleic acid
what is dna made up of
nucleotiddes
what contains the instruction for proteins
a gene
what is dna organised in
arranged chromsomes
is a gene larger than a chromsome
no a chromosome is larger than a gene
how many bases does ammino acids code for
3
how many types of nuclleotides are there
4
what is each nucleoid made up of
a phophate group, a base and a simple pentose sugar
what has alternating sugar and phophate section
long strands of DNA
what sends instruction for a particular sequcne of amino aicds, to make specific proteins
each gene
what is A paired with
T
what holds the base pairs and two strands together
weak hydrogen bonds
what are the four bases in dna
- adenine (A)
2.Thymime (T) - guanine (G)
- cytosine (C)
what can turn the genes on or off in a cell
non coding dna parts
what is C paired with
G
what do ribosome do
carry out protein synthesis in the cytoplasm of the cell
does all dna codes proteins
no
what could poteintially effecgt how genes are expressed
mutations
how many levels of organisattion in a genome
3
what are the three names of the levels of organisation in a genome
dna, chromomsomes and genes
what happens if a mutation codes for a sligtly altered enzyme protein with a diffrent shape
an enyme may no longer fit the substrate bidning site
whar brings ammino acids to the ribosome
carrier molecules
what three thing are made from proteins genes, send instructuons to create the protein needed from amino aicds
enzymes, horomes and antibodies
what is the role of RNA polymerase
too bind to non coding dna in front of the gene and produce a complementary mRNA strand from tge codubg DNA of the gene
what does the order of bases control
the order the amino acids are formed to produce a singular protein
what does a protein chain form when completed
a uniqye shape which allows the protein to carry out its role effectively, its role could be as an enzyme or a hormone
what happens when mutations occur over time
there can be genetic variants
what happens before transcription occurs
RNA polymerase binds to the non coding part of the DNA in front of the gene
what was mendel’s hypothesis
- the inits of inheritance are passed on to offspring unchanged
2.characteistics are held as sepeare units of inheritance - each unit of inheritance exists in two forms, dominant and recessive
what will happen if a mutation occurs in the non coding part of the DNA
the mutation could effect how well the RNA polymerase can bind to the non coding part of the \dna
what did mendel propsed the unit of inheritance as
genes
why did scientist not undestrand mende;’s work
scientist didn;t have microscopes and therefore didn’t know about the existence of chromosomes
what did mendel study
inheritance of certain charactersitics in peas, while working in the monstery gardens observed if he crossbread white and red flowers. the red flowers were more dominant than the white
name two characteruitcs controlled by a single gene
hair colur and eye colour
each allele codes for a diffrent….
protein
what is red green colour blindness due to
the mix of allels they possess
what is inheritance
when living things reproduce and pass on characteristics to their offspring in genes
what does homozygous mean
when two allels are the same
what represents a homozygous allel
either two capital letters or two lower case
what represents a hydroxygous allele
a capital and a lower case
what does hetrozygous mean
when two allels are diffrent
what is a genotype
the set of genes that an organism has
what is a phenotype
the physical characterisitc of an organism
what does dominant mean
an allele that controls the characteristic whenver presented, capital letter
what does reccessive mean
an allels who characterisitcs only show up when its present on both chromosomes
what chromosomes do girls have
xx
what chromsomes do boys have
xy
why can you get the same sex
because fertillisation is random
what does it mean if a conditionis caused by a dominant allele, one of the parents has the condition but there are some offspring without the condition
the parents condition must be hetrozygous
what is a genetic cross
a way of modelling potenital outcome from mating two parents where the phenotype and genotype are usually know
why do we use characteristics that are controlled by a single gene
it is easy to see the effect in the next generation and beyond
who is ffamous for creating the punett square diagram
british genetiscist reginald punnet
what is a punnett square
a tool used to predict the probality of genotypes in future off spring
what ddoes a family tree help do
to show how genetic disorders are inherited in a family
what are family tees used to do
workout the probablity thatva member of the family will inherit a disorder
what is colour blindness
a sex linked genetic disorder that a person is born with
what causes colour blindness
a faulty alele carried on the x chromsome
which one is bigger the x or y chromsome
x
why are more men than women are affected by the disorder
women need two copies of the faulty recessive allele to be colour blind, whilst men only need one copy
is blood group inherited
yes
how many possible blood groups are there
4
what are the names of these 4 possible blood groups
- A
- B
- AB
- O
how many diffrent allels does the gene for blood have
three
what are the three diffrent allels that the gene for blood has
: IA , IB and IO
what two allels fr blood groups are co dominant
IA and IB
what does it mean if a person is codominatn
if a person has the genotype IA and IB then they are blood group AB. Both allels are equally as dominant
which of the four possible blood groups is recessive
IO
how many of the chromosomes control characteristics
22
what are sex chromomes
the 23rd pair of chromsomes that carry the genes that determine sex
because sex chromomes are not identical to each other, what are they called
x and Y
at what stage is sex determined at
fertillisation
why is there a 1in 2 chance of the offspring being male/female
becayse it depnds on whether a sperm containing an x chromosome or Y chromosome fertillises the egg and there are equal numbers of these
what do the genome and its interaction with the environment influence
the development of a phenotuype in an organism
varation within a population of a species is usually..
extensive, mostly arising from mutations
what is produced from the same egg and sperm
identical twins, they show very little/no genetic variation
what is a result of multiple genes interacting rather than single gene inheritance
most phenotypic features
can continous or discontinous data take any value between two limits
continous
what is continous varation
when the diffrence in chracteriscs is continous
what are examples of continous data
lenth mass time
does continous or disconitnous data values only have on set of number option
discontinous
what is discontinous varaition
when difference in characterics are discontinous
what are exxamples of discooontinous data
shoe size a blood group
would you use a bar graph/historgam for discontinous or continuous data
discontinous
would you draw a line graoh for cintinous or discontinous data
continus
what is envriomental variation caused by
how the enviroment effewcts the individual
what is genetic variation causedby
the diffrence in allels
what are 3 factors influenced by both gentic and environmental variation
- skin colour
- weight
- altheticism
name 5 human phenotypes which are cuased by genetic variation
- eye colour
- natural hair coloue
- nose shape
- ear lobe shape
- blood group
name 5 human phenotypes i9nfluncd by enviromental variation
- hair length
- accents
- tatoos
- scars
- language spoken
what are three causes of variation
- diffrences in enviromental conditions have led to vairation
- diffrences in the genes indivudlas have inherited due to mutation and sexual reproduction
3, a combination of both genetic and environmental causes
what is the human genome prohect
an international scientific research prohect set up to map all the genetic info in a human being
3 reasons why the human genome is important
- to enable scientists to search for the genes linked to different types of disease to look for possible treatment or correction
- to enable doctors to better understand and treat inhetiedd disorders
3, to be able to trace historic human migration patterns
where can mutations occur
in a gamete or body cell
where do genetic variation arise rom
mutations
what occurs continously during cell division
mutations
do genetic mutation alter the phenotype
no, bur some will have a small effect on the phenotype
what can happen if a phenotype is suited to an environmental change
can lead to a relatively rapid change in the species
what is mutation
a change in the dna sequence of a gene
how many types of mutatations are there
4
what are the names of the 3 types of mutation
insertion deletion subsition and neutral
what are are carcinogerns
cancer causing mutations
what is a spontanous mutation
a mistake made when dna is copied during the production of gametes
what does does it mean if there is a spontaneous mutation
that the mutation wil be inherited by the offspring after fertilization
what increases the chances of mutation
radiationsa
what are mutagens
anything thaat causes a mutation
if you smoke what aare you more likely to get
carcingens
what do useful mutations help a species to do
adapt to an enviroment and give a species an advantage
what would happen if there is a mutation in the non coding part of the DNA
may result in RNA polymerase not binding well reducing trasnciption. other non coding mutations can result in RNA polymerase binding better and producing mRNA
