Inheritance DNA & Evolution - DNA & Inheritance Flashcards
what is DNA classed as and what structure does it have
polymer
double helix structure
what is DNA made up of
chromosomes
what are genes
small section of DNA found on a chromosome
what does a gene do
codes for a particular sequence of amino acid which are put together to make a specific protein
how many amino acids are used
20 but they make thousands of different proteins
what determines what type of cell something is
dna determines what protein the cell produces that in turn determines what cell it is
what is a genome
entire set of genetic material in an organism
what is understanding the human genome important for
identifying genes that are linked to diseases
so can develop effective treatment for them
can trace migration of populations of people around the world. Scientist study differences in genome to work out when new pops slit off
DNA is made of repeating units called what
nucleotides
what do nucleotides consist of
one sugar molecule and one phosphate molecule and one of 4 bases
the sugar and phosphate molecules alternate and the base sticks out
what are the 4 bases of DNA
A C G T
what decides the order of amino acids in a protein
order of the base in a gene
each amino acid is coded by what
sequence of three bases
how is DNA kept in a helix structure
each base is linked to a base on the opposite side of the structure.
A pairs with T
C pairs with G
this is called complementary base pairing
what do non coding parts of DNA do
switch genes on and off. so control if gene is expressed (used to make a protein)
where are proteins made
in cytoplasm on structures called ribosomes
what do ribosomes use to know how to make proteins
code in DNA
how does the ribosome get the code from the DNA
a molecule called mRNA carriers the copied code and acts as a template
how are the correct amino acids brought to the ribosomes in the correct order
by carrier molecules
what happens when a chain of amino acids has been assembled
folds into unique shape
what are 3 functions of proteins
enzymes
hormones
structural proteins
what is a mutation
a random change in an organisms DNA
can sometimes be inherited
when do mutations happen
continuously.
e.g spontaneously when a chromosome isn’t replaced properly
chances increase by exposure to certain substances or some types of radiation
what do mutations do
change the sequence of DNA bases in a gene which produces a genetic variant
this can lead to changes in the protein it codes for which will effect its ability to perform its function
however most mutations have very little or no effect on the protein
what is an example of how a protein may not work due to mutation
collagen could lose strength if shape is changed
what are insertions
a new base is inserted into DNA base sequence where it shouldn’t be . This causes the way the group of 3 bases for an amino acid is read which can change the amino acid. Insertions can change more than one amino acid as they have a knock on effect on the bases further in the sequence
what are deletions
random base is deleted from dna which changes the way the base is read and has knock on effects further down the sequence
what is a substation
mutation where random base sequence is changed to a different base
what is sexual reproduction
where genetic infomation from 2 organisms is combined to produce offspring genetically different to each parent
what does a gamete contain
23 chromosomes so one of each chromosome
what is fertilisation
egg and sperm fuse together to form a cell with full number of chromosomes
what is asexual reproduction
one parent so clone is identical. happens by mitosis
what happens in meiosis
cell duplicates genetic information forming 2 armed chromosomes and arrange themselves into pairs
line up in centre of cell then pull apart so each new cell only has one copy of each chromosome
they line up and split again
then the chrosomes end up random thAT ARE IN THE 4 GANETES FORMED
what happens in embryo development
cells divides using mitosis to produce lots of new cells. as embryo develops they begin to differentiate into specialized cells
advantages of sexual reproduction
variation because of mixture of 2 sets of chromosomes
this increases species chances of surviving a change in environment because individuals willhave charecteristics that make them better adapted
they will then breed and ass their characteristics
selective breeding speeds up natERAL SELECTION so we can increase food productionon
advantages of asexual reproduction
only needs to be one parent so less energy and faster
many identical offspring can be produced in favourable conditions
how can malaria produce offspring
parasite transfered to human in mosqito bite and produces asexually
produces sexually when its in the mosquito
what can produce sexually and a sexually
fungus
what are runners
stems that grow horizintally away from plant which is an asexual reproductive method by strawberrys
