Inheritance Flashcards
genome
entire set of genetic material
what is a gene made up of
small section of DNA
What does a DNA code for
sequence of amino acids
alleles
different version of a gene
homozygous alleles
having 2 alleles of same type
heterozygous alleles
having 2 alleles that are different to one another
genes function
control our characteristics as they code for proteins that play important roles in what our cells do
what are chromosomes
DNA double helix supercoils
DNA full name
deoxyribonucleic acid
what is DNA
genetic material found in the nucleus of cell
what is DNA made up of
polymer made up of 2 strands coiled around to make a double helix
what are the DNA strands formed from
sugar-phosphate backbone with bases joined togehter
complementary base pairing rule
Adenine- Thymine
Guanine- Cytosine
what relies on the base pairing rules
cell division and protein synthesis
what does the DNA double helix acts as
template to be copied in order to create new double helix
RNA full name
ribonucleic acid
what is a polynucleotide
made up of many nucleuotides linked together in a long chain
what does RNA contain instead of Thymine
uracil
what are RNA molecules made up of
one polynucleotide stand
(single stranded)
what are RNA polynucleotide stands made up of
alternating ribose sugars and phosphate groups linked together with nitrogenous bases of each nucleotide projecting out sideways.
example of RNA molecules
messenger RNA
What does messenger RNA do
transcript copy of a gene that encodes a specific polypeptide
what is a gene
sequence of nucleotide bases in a DNA molecule that codes for the production of amino acids
2 stages of protein synthesis
1) transcription
2) translation
transcription
DNA transcribed and mRNA molecule is produced
translation
mRNA is translate and an amino acid sequence is produced
where does transcription occur
nucleus
when do DNA molecules unwind
when hydrogen bonds break
what happens once hydrogen bonds break
exposes template stand of the gene that codes for the protein being synthesised
what binds to complementary nucleotides during transcriptions
free mRNA nucleotides that are present in nucleus
where does translation occur
cytoplasm
where does mRNA molecule attach after leaving nucleus
ribosome
what is anticodon
tRNA molecules which have triplet of unpaired bases at one end
what does a anticodon correspond to
specific amino acid
what does anticodon pair to
codon
what attaches to complementary codon
a second tRNA molecule and a peptide bond formed between 2 amino acids
when does translation stop
until a stop codon on the mRNA moleluce is reached.
phenotype
observable characteristics of an organism
genotypes
combinatoin of alleles that control each characteristics
dominant allele
need to be inherited from one parent for characteristic to show up
recessive allele
needs to be inherited from both parents in order for characteristics to show up
homozygous dominant
having 2 copies of dominant allele
homozygous recessive
having two copies of recessive allele
dominant allele shown as
capital letter
recessive allele shown as
lower case
pure breeding
2 individuals with identical homozygous for a characterisitc a, are bred they produce offspring with exactly the same genotype and phenotype
codominance
both alleles within genotype are expressed in phenotype
example of codominance
inheritance of blood group
Which bloodgroups are codominant
blood group A and B
blood group O
no antigens produced in blood
blood group B
produces antigen B
blood group A
produces antigen A
Polygenic
characteristics that are controlled by more that one gene
polygenic inheritance
inheritance of polygenic characteristics
monohybrid inheritance
inheritance of characteristics controlled by a single gen e
punnett square
shows possible combinations of alleles that could be produced in offspring
family pedigrees
used to trace the pattern of inheritance of specific characteristics, normally a diseases
family pedigrees- males
sqaure shaped
family pedigrees- female
circles
family pedigrees- affected or not
affected- red
unaffected- blue
female sex chromosome
XX
Male sex chromosome
XY
mitosis
nuclear division giving rise to genetically identical cells
mitosis uses
growth
repair
replacement of celles
what ensures cell splits into 2
cell divide chromosomes double - duplication
process of mitosis
- each chromosome in nucleus copies
- chromosome line up along centre of cell where cell fibres pull them apart
- cell divides into 2, each cell have copy of each chromosomes
meiosis
nuclear division that gives rise to cells genetically different
what is used to produce gametes
meiosis
meiosis process
- each chromosome makes identical copies of itself
- first division:
chromosomes pair along center, recombination occurs and cell fibers will pull pairs apart, each new cell will have one of each recombinant chromosome pair - chromosome line up along centre of celll, cell fibres will pull them apart
- 4 hapolid daughters produced
important of meiosis
- production of gametes
- increased genetic variation
causes of phenotypic variation
- genetic
- environmental
what creates genetic variation between zygotes
random fusion of gametes
examples of genetiec variation
blood group
eye colour
gender
discontinuous variation caused by
genetic varation
variation
differences between individuals of the same species
continuos variation
when there are very many small degrees of differences between individuals
Discontinuous variation
when there are distinct differences for a characteristic
mutations
rare, random changes that occur in sequence of DNA bases in gene or chromosome
what can mutation in a gene lead to
change in protein that the gene codes for
insertions
new base is randomly inserted into a DNA sequence
what do insertion mutation change
changes the amino acid that would have been coded
what insertion mutation have an effect on
chaging groups of 3 bases further on in the DNA sequence
deletions
a base is radomly deleted from the DNA sequence
what does a deletion change
changes the amino acid that would have been coded
substituition
a base in the DNA sequence is randomly swapped for a different base
what does a substituition change
only change amino acid for the group of three bases in which mutation occurs
mutation effects
- new alleles/phenotypes
- sickle cell anaemia
sickle cell anaemia mutation
changes the molecule haemoglobin caused the RBC to become stiff and sickled shape
what does sickle cell anaemia do
get stuck in narrow blood vessels and block the flow of blood
what can sickle cell anaemia lead to
strokes, blindess, damage to lungs
what increases the chance of mutation
gamma rays, UV rays, types of chemicals (tar)
who came up with the theory of evolution
Charles Darwin
evolution
change in frequency of a phenotype in a population over many generations
explain Darwins theory
- individuals with characteristics most suited to environment have a higher chance of survival
- characteristics passed to their offspring at a higher rate
- beneficial characteristics become more common in the population
what is natural selection known as
survival of the fittest
natural selection answer
-Within a species, there is always variation and chance mutation
-Some individuals will develop a phenotype (characteristic) that gives them a survival advantage and this allows them to: live longer, breed more be more likely to pass their genes on
Repeated over generations, the ‘mutated’ phenotype will become the norm
antibiotics
chemical substances made my certain fungi or bacteria that affect bacterial scells
2 types of antibiotics
- disrupt structure of function
- prevent them from reproducting
how does antibiotic resistance occur
random mutations in their DNA
what developed resistance to methicillin
Staphylococcus
prevention of resistance bacteria
- no overuse of bacteria
- only in serious cases
- finish whole course of antibiotics
why do antibiotics not work on viruses
antibiotics work by disrupting cell functions such as respiration, or breaking down the structure of the cell in some way
However, viruses do not carry out any cell functions
