Genetic Diversity Can Arise As A Result Of Mutation Or During Meiosis Flashcards
What is the name of a cell that contains two of each chromosome
Diploid
Chromosomes that make up a pair have the same …. and same… but have different …
Size
Genes
Alleles
What are the gametes in males and females
Sperm
Egg
What is the name for cells that only contain half number of chromosomes
Haploid
Abbreviation for haploid and diploid
Haploid - n
Diploid - 2n
How many chromosomes does a human cell contain
46 chromosomes
23 pairs of chromosomes
How may daughter cells are produced during meiosis
4
Meiosis produces daughter cells that are genetically different/ the same
Different
Does meiosis produce haploids or diploids
Haploid
How many divisions is meiosis
2
When does crossing over and independent segregation occur during meiosis
First round of division
Meiosis 1
How to calculate number of possible combination of homologous pairs
2^n
Aka 2^23 because 23 pairs of homologous pairs
What is independent segregation
When the homologous chromosomes separate in the 1st round of division in meiosis you can have any combinations of maternal and paternal chromosomes
What does crossing over and independent segregation result in overall
Genetic variation
Differences between mitosis and meiosis x3
Meiosis vs mitosis
Two divisions vs one divisions
Produces haploid vs produces diploid
Genetically different vs genetically identical
Top tip for when doing life cycles
2n and n
These will always be there label them
When is there additional variation excluding meiosis + formula
Fertilisation because more possible combinations of chromosomes
(2^23)^2
What is a gene mutation (generic)
When a gene mutation is when there is a change to the base sequence of chromosomes
When do mutations in DNA occur
Spontaneously during DNA replication
Why is mutations in DNA bad
The different base sequence results in different amino acid sequence in the polypeptide
This means different bonds E.g. ionic bonds and the polypeptide will fold differently
Can’t carry out its function properly
What are the two types of mutation
Substitution
Deletion
What does degenerate mean
Amino acids are coded for by more than one DNA base triplet
Which one will definitely change the protein produced
Deletion always
What are mutagenic agent
Substances that increases the rate of mutation and lead to cancer
What are the two types of mutagenic agent
High energy and ionising radiation
Carcinogens
Names three carcinogens
Tobacco smoke
Mustard gas
Peroxides
What is non-disjunction and when does it happen
When the chromosomes fail to separate
Meiosis 1 or 2 (less commonly mitosis)
How does fertilisation increase genetic variation
RANDOM fertilisation
New alleles combinations produced
How can a new allele have no effect on individual
New allele is recessive so does not influence phenotype
How can a mutation be advantageous
Results in change in polypeptide that positively changes the properties of the protein
May result in increased survival changes
What one thing can effect rate of mutation
The environment
What does is mean by the genetic code is non-overlapping
Base triplets do not share bases
What is a homologous chromosome
Matching pair of chromosomes
What is it called when a base is deleted so all the base triplets move
Frame shift
