Genes And Inheritance Flashcards
What is an allele
An allele is a different form/version of the same gene (e.g. Different base sequence in the DNA)
There are two strands coiled to form the double helix DNA. One is copied to make proteins, what is the other one for?
Protection
Where are chromosomes found?
In the nucleus of a cell
Where are genes located
On chromosomes
What is a gene
A section of a molecule of DNA. It codes for a specific protein,
What is a mutation
A change in the sequence of bases in DNA, it causes different forms of a gene (allele)
What does mitosis produce
Identical cells. Some organisms use it for asexual reproduction
What does meiosis produce
Gametes which are haploid for sexual reproduction
How many chromosomes are there in a nuclei of a body cell
46
What combination of x and y do you have if you’re a girl
XX
What combination of x and y do you have if you’re a boy
X Y
Dominant definition
Only one allele needs to be like this for the characteristic to appear
Recessive definition
Both alleles need to be recessive for the characteristic to appear
Homozygous definition
When the two alleles in a pair are the same
Heterozygous definition
When the two alleles in a pair are different
Phenotype definition
The physical characteristic of an organism
Genotype definition
The collection of genes inside the nucleus
Codominance definition
When the phenotype is affected by both alleles working in combination
What does mitosis help with
Growth, repair, cloning and asexual reproduction
How does meiosis produce gametes?
It begins with a single cell (diploid) which makes a copy of each chromosome. The cell then divides into two (haploid) then each cells divides into 2 again so you have 4 haploid cells that are all genetically different.
What is a mutation (general)
A rare random change in genetic material that can be inherited.
The theory of evolution by natural selection
Evolution happen by natural selection. Since there is competition for resources in the natural world only those most suited to their environment can survive and pass their genes onto the next generation. Mutations in genetics can also lead to population variation giving some individuals an advantage or disadvantage.
What are the 4 bases of a DNA nucleotide
Adenine
Guanine
Cytosine
Thymine
Process of bacteria becoming antibiotic resistant
Bacteria reproduce very frequently. During reproduction mutations may occur and some mutations can cause bacteria to become resistant to antibiotics, if the full course of antibiotics are not taken resistant bacteria will survive. These resistant bacteria will multiply until the whole population is resistant to antibiotics.
How can the likeliness of mutation be increased
Exposure to ionising radiation (gamma, X-ray, ultraviolet) and some chemical mutagens (chemicals in tobacco)
