Topic 9- Key Terms

Question 1

Define Genetic Diversity

Answer 1

Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species

Question 2

Define Mutations

Answer 2

A permanent, heritable change in the nucleotide sequence in a gene or a chromosome; the process in which such a change occurs in a gene or in a chromosome

Question 3

Define Substitution

Answer 3

It is a mutation that exchanges one base for another

Question 4

Define Deletion

Answer 4

It is a mutation in which a part of a chromosome or a sequence of DNA is lost during DNA replication. Any number of nucleotides can be deleted, from a single base to an entire piece of chromosome.

Question 5

Define A Frameshift

Answer 5

It is a genetic mutation caused by indels (insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three.

Question 6

Define Chromosome Mutations

Answer 6

These mutations can involve deletions, additions, or inversions substitutions of sections of DNA.

Question 7

Define The Term Polyploidy

Answer 7

It is the state of a cell or organism having more than two paired (homologous) sets of chromosomes

Question 8

Define Homologous Chromosomes

Answer 8

A homologous pair is a pair of chromosomes containing a maternal and paternal chromatid joined to together at the centromere. They have the exact same gene - although may have different alleles of these genes

Question 9

Define Gene Pool

Answer 9

The total number of alleles in a particular population at a specific time.

Question 10

Define Meiosis

Answer 10

The type of nuclear division in which the number of chromosomes is halved

Question 11

Define The Diploid Cell

Answer 11

A cell containing homologous pairs of chromosome (maternal and paternal). The diploid number for humans is 46.

Question 12

Define The Haploid Cell

Answer 12

A cell containing one complete set of chromosomes. The haploid number for humans in 23.

Question 13

Define Locus

Answer 13

A fixed position on a particular DNA molecule occupied by a gene

Question 14

Define Gene

Answer 14

The base sequence of DNA (along the chromosome) that codes for the amino acid sequence of a polypeptide or functioning RNA.

Question 15

Define Sister Chromatid

Answer 15

One-half of a chromosome that has undergone semi-conservative DNA replication

Question 16

Define Allele

Answer 16

One of the different forms of a gene

Question 17

Define Genetic Variation

Answer 17

Variation describes differences in the genetic make-up between individuals within a species

Question 18

Define Crossing Over

Answer 18

The process whereby a chromatid breaks during meiosis and rejoins to the chromatid of its homologous chromosomes so their alleles are exchanged.

Question 19

Define Independent Segregation

Answer 19

Is due to the random orientation of pairs of homologous chromosomes in meiosis I

Question 20

Define Phenotype

Answer 20

Refers to the observable physical properties of an organism; these include the organism’s appearance, development, and behavior.

Question 21

Define Directional Selection

Answer 21

Is a force in nature that causes a population to evolve towards one end of a trait spectrum
Happens when the environment changes

Question 22

Define Stabilising Selection

Answer 22

Which the population mean stabilizes on a particular non-extreme trait value.
When the environment stays the same

Question 23

Define Selection Pressure

Answer 23

Any cause that reduces reproductive success in a portion of a population

Question 24

Define Genotype

Answer 24

The set of genes the organism carries, as well as by environmental influences upon these genes.

Question 25

Define Gamete

Answer 25

The reproductive cell that fuses with another gamete of the opposite sex during fertilization

Question 26

Define Gene Mutations

Answer 26

A permanent alteration in the DNA sequence that makes up a gene

Question 27

Define Non-Disjunction

Answer 27

Refers to the chromosomes failing to separate correctly, resulting in gametes with one extra or one less chromosome

Question 28

Define Recombination

Answer 28

A process by which pieces of DNA are broken and recombines to produce new combinations of alleles creates genetic diversity

Question 29

Define Species

Answer 29

A group of similar organisms that can breed together to produce fertile offspring

Question 30

Define Allele Frequency

Answer 30

Refers to how frequently a particular allele appears in a population

Question 31

Define Polygenes

Answer 31

Refers to a group of genes that when expressed together produce a particular phenotype or trait

Question 32

Define Normal Distribution Curve

Answer 32

A theoretical frequency distribution for a random variable characterized by a bell-shaped curve.