DNA is genetic instructions. What functions do they preform in the body?
Instructions on how the body is formed and how it functions.
When a cell undergos mitosis, what does it’s DNA gets organised in to?
Into chromosomes.
How many pairs of chromosomes are in the body?
23 pairs or 46.
Of the 23 pairs, one pair is a sex chromosome. What are the remaining 22 pairs called?
The remaining 22 pairs are autosomes.
What is the function of the 22 pairs of autosomes in the body?
These guide the expressions of most of the other traits in the body.
What is a gene?
A segment of DNA that carries instructions for a particular trait or characteristic. You get two copies, one from each parent.
Define allele?
It is a matched pair of genes in the same position on homologous chromosomes. Eg Gene = ear wax Alleles = wet or dry.
What is the difference between a dominant and recessive gene?
Dominant gene is always expressed when present - thought of as stronger.
Recessive gene are only expressed if there are two copies when the dominant allele is absent. Thought of as the weaker gene.
What is the difference between a geneotype and phenotype?
A genotype is the genetic make up - inherited genes, where you get two copies, one from each parent.
A phenotype is the physical expression of occurs as a result of the gene.
A genotype can be describe as the same or different genes. What are the correct terminology you give these?
Homozygous - 2 alleles in a person are the same.
Hetrozygous - 2 alleles are different - 1 dominant and 1 recessive.
Inheritance is the process of genetic transmission of characteristics from parents to offspring. One of the processes is independent assortment of chromosomes, what are the other two?
Crossing over homologous chromosomes.
Random fertilisation.
There are four types of inheritance that most traits are determined by multiple alleles or by interaction of sever gene pairs. The first one is single gene inheritance. What are the other three?
Single gene inheritance - where one gene controls expression of specific characteristic.
Sex linked inheritance - genes present x shaped sex chromosome.
Multiple allele inheritance - where there are two or more possible alleles.
Polygene inheritance - 2 or more genes influence specific characteristic.
