Genetics - Key Terms

Question 1

What is the Phenotype?

Answer 1

Physical characteristics of an individual organism (can include non-visual things e.g. Disease).

Question 2

What is the Genotype?

Answer 2

The genetic makeup of an individual organism.

Question 3

What is an Allele?

Answer 3

A version of a gene.

Question 4

What does Aneuploidy mean?

Answer 4

When an organism has an extra chromosome, usually as a result of the failure of chromosomes to separate during division.

Question 5

What does Polyploidy mean?

Answer 5

When an organism has one or more extra sets of chromosomes, meaning their gametes have more than the haploid number of chromosomes.

Question 6

What does haploid mean?

Answer 6

the number of chromosomes that are in a normal gamete of an organism e.g. humans haploid number is 23.

Question 7

What does diploid mean?

Answer 7

double the haploid number, the number of chromosomes in a body cell.

Question 8

What does homozygous mean?

Answer 8

A genotype containing two of the same alleles.

Question 9

What does Heterozygous mean?

Answer 9

A genotype containing two different alleles.

Question 10

What does Dominant mean?

Answer 10

The individual only requires one dominant allele to express the dominant phenotype (physical characteristics)

When a genotype is heterozygous and contains 2 different alleles, the phenotype is whatever is the dominant phenotype.

Question 11

What does Recessive mean?

Answer 11

The individual requires both recessive alleles to express the recessive phenotype.

Question 12

What is the Locus?

Answer 12

The location of a gene on the chromosome (plural: loci)

Question 13

What is a chromosome?

Answer 13

a thread-like structure that carries the genes in the nucleus.

Question 14

What is a Codon?

Answer 14

a sequence of three nucleotide bases in RNA that codes for a specific amino acid.

Question 15

what is an Exon?

Answer 15

a coding region of DNA.
They are transcribed to the final mRNA molecule.

They contrast with introns which are non-coding regions that are spliced out from the tRNA molecule.

Question 16

What is a Gamete?

Answer 16

A gamete is a sex cell.

Gametes are produced by meiosis. They have half the number of chromosomes found in somatic cells.

Question 17

what is cell potency?

Answer 17

Cell potency refers to the varying ability of stem cells to differentiate into specialised cell types.
Cells with the greatest potency can generate more cells types than those with lower potency.

Question 18

what does multipotent mean?

Answer 18

Multipotent cells can develop into more than one cell type, but are more limited than pluripotent cells.

Adult stem cells are considered multipotent.

Question 19

what does pluripotent mean?

Answer 19

Pluripotent cells can give rise to all of the cell types that make up the body.
Embryonic stem cells are considered pluripotent.

Question 20

what does totipotent mean?

Answer 20

Totipotent cells can form all the cell types in a body, plus the placental cells.
Embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent.