4.6.1.6 Genetic inheritance Flashcards
1
Q
Explain the term gamete.
A
- It is haploid, containing only one set of dissimilar chromosomes
2
Q
Explain the term chromosome.
A
- A chromosome is a thread-like structure made of DNA and proteins found in the nucleus of cells
3
Q
Explain the term gene.
A
- A segment of DNA that codes for a particular type of protein
4
Q
Explain the term allele
A
- Different versions of the same gene
5
Q
Explain the term dominant.
A
- Always expressed even if only one copy is present
6
Q
Explain the term recessive.
A
- Only expressed if two copies are present (therefore no dominant allele present)
7
Q
Expand the term homozygous.
A
- If the two alleles present are the same
8
Q
Explain the term heterozygous.
A
- If the two alleles present are different
9
Q
Explain the term genotype.
A
- The chemical composition of an organism’s DNA that gives rise to its observable traits (phenotype).
10
Q
What characteristics are controlled by a single gene?
A
- Fur colour in mice
- Red-green colour blindness in human
- Each gene may have different forms called alleles
11
Q
Explain the term phenotype.
A
- The observable physical properties of an organism; these include the organism’s appearance, development.
12
Q
Why do the allele or genotype present operate at a molecular level?
A
- To develop characteristics that can be expressed as a phenotype
13
Q
When is a dominant allele expressed?
A
- Always expressed even if only one copy is present
14
Q
When is a recessive allele expressed?
A
- Only expressed if two copies are present (therefore no dominant allele present)
15
Q
When is an organism homozygous?
A
- If the two alleles present are the same
16
Q
When is an organism heterozygous?
A
- If the two alleles present are different
17
Q
What are most characteristics a result of?
A
- Multiple genes interacting rather than a single gene
