Topic 4B- Diversity and Selection Flashcards
mutation
a change in the DNA base sequence
substitution
1 base sis swapped for another based
deletion
a base is removed
addition
a base is added
translocation
a sequence of bases are moved
polygenic
many genes
is translocation a gene or chromosome mutation
chromosome
stomatic cell
any body cell, anything bit a gamete
gamete
sex cell
are mutations random
yes
duplication
at least one base is reapeated
inversion
a sequence of bases are reversed
a mis-sense mutation
different amino acids is coded for, altering the primary structure
what will happen is an enzymes primary structure is changed
the tertiary structure changes therefore affecting the active site of an enzyme- substrate can no longer fit in
silent mutation
the base changed doesn’t affect the tertiary structure as the coe is degenrate
degenerate
more than 20 triplet codes compared to the 20 amino acids
nonsense mutation
the change in a triplet codes for a stop mutation therefore the rest of the RNA isn’t read during transcription
frame shift
altering the order of the triplets this can be die to a deletion or addition
where may a mutation occur and it have less consequences
an end of a gene or introns
gene expression
the process of transcription and translation
mutagens
environmental condition or substance which increases the rate of a mutation occuring
examples of mutagens
- pollution
- radiation
- alchohol
- some viruses
carcinogens
something that mutates DNA in the genes that replicate- causing cancer
what type of cell undergoes meiosis
gametes
zygote
first fertilised cell of gametes
diploid
full set of chromosomes (46)
haploid
half set of chromosomes (23)
homologous
same pairs of chromosomes
alleles
different version of the same gene
example of different alleles
eye colour
what type of division is meiosis and why is it needed
reduction division, to get the correct number of chromosomes
how many haploid daughter cells does meiosis produce
4
locus
position on chromosome where a gene is found
how many stages does meiosis take
2
are the cells produced in meiosis genetically identical
no
genetic diversity
total number of different alleles within a population
population
total number of one species in an area at a given time
gene pool
total number of alleles of all genes in a population
what makes a population more stable
larger number of alleles
larger number of genes =
able to resist environmental change
example of environmental change
temperature increase
how does variation occur
mutations
gene flow
an organism of the same species but different population mixes with another population
what does lots of gene flow result in
genetically similar populations
how does increasing number of alleles in a population occur
mutations and gene flow
types of reducing genetic diversity
genetic bottleneck and founder effect
genetic bottle neck
reduction in populations due to a catastrophe
founder effect
the loss of genetic variation when a new population is established from a very small number of individuals from a larger population
ethical ideas of selective breeding
-if it effects organism well being
-what diseases could be spread
negatives of selective breeding
-loss of alleles entirely
-population is less resistant to change
