Unit 3 List 2 DNA & Heredity

Question 1

Define allele

Answer 1

One of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Question 2

Define centromere

Answer 2

The region of a chromosome to which the microtubules of the spindle attach, via the kinetochore, during cell division.

Question 3

Define chromatid

Answer 3

A chromatid is one of the two identical halves of a chromosome that has been replicated in preparation for cell division.

Question 4

Define chromosomes

Answer 4

A threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Question 5

Define codon

Answer 5

A sequence of three consecutive nucleotides in a DNA or RNA molecule that codes for a specific amino acid.

Question 6

Define crossing over

Answer 6

A cellular process that happens during meiosis when chromosomes of the same type are lined up.

Question 7

Define daughter cell

Answer 7

Either of the two cells formed when a cell undergoes cell division by mitosis.

Question 8

Define Deletion

Answer 8

In genetics, a deletion is a mutation in which a part of a chromosome or a sequence of DNA is left out during DNA replication.

Question 9

Define Diploid

Answer 9

Containing two complete sets of chromosomes, one from each parent.

Question 10

Define DNA

Answer 10

DNA is made up of a double-stranded helix held together by weak hydrogen bonds between purine-pyrimidine nucleotide base pairs.

Question 11

Define Fertilization

Answer 11

When sperm and an egg join together.

Question 12

Define Frameshift

Answer 12

A genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read.

Question 13

Define Gamete

Answer 13

A mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote.

Question 14

Define Gene

Answer 14

The basic unit of heredity passed from parent to child.

Question 15

Define Gene Mutation

Answer 15

A change in one or more genes.

Question 16

Define Genetic Code

Answer 16

The genetic code is the set of rules used by living cells to translate information encoded within genetic material into proteins.

Question 17

Define genetic variation

Answer 17

A term used to describe the variation in the DNA sequence in each of our genomes.

Question 18

Define Haploid

Answer 18

A cell that contains a single set of chromosomes.

Question 19

Define homologous chromosomes

Answer 19

The two chromosomes in a homologous pair are very similar to one another and have the same size and shape.

Question 20

Define independent assortment

Answer 20

The Principle of Independent Assortment describes how different genes independently separate from one another when reproductive cells develop.

Question 21

Define Insertion

Answer 21

The act of putting one thing into something else, or of adding something to something else.

Question 22

Define meiosis

Answer 22

Meiosis is a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes (the sex cells, or egg and sperm).

Question 23

Define meiosis l

Answer 23

Meiosis I is a type of cell division unique to germ cells, while meiosis II is similar to mitosis.

Question 24

Define meiosis ll

Answer 24

Meiosis I is followed by meiosis II, which resembles mitosis in that the sister chromatids separate and segregate to different daughter cells.

Question 25

Define monosomy

Answer 25

Monosomy refers to the condition in which only one chromosome from a pair is present in cells rather than the two copies usually found in diploid cells.

Question 26

Define mutagen

Answer 26

Anything that causes a mutation (a change in the DNA of a cell).

Question 27

Define mutation

Answer 27

Any change in the DNA sequence of a cell.

Question 28

Define nondisjunction

Answer 28

Nondisjunction means that a pair of homologous chromosomes has failed to separate or segregate at anaphase so that both chromosomes of the pair pass to the same daughter cell.

Question 29

Define offspring

Answer 29

In biology, offspring are the young creation of living organisms, produced either by sexual or asexual reproduction.

Question 30

Define parent cell

Answer 30

A cell that is the source of other cells, as a cell that divides to produce two or more daughter cells, or a stem cell that is a progenitor of other cells or is the first in a line of developing cells.

Question 31

Define point mutation

Answer 31

A genetic alteration caused by the substitution of a single nucleotide for another nucleotide.

Question 32

Define replication

Answer 32

The action of copying or reproducing something.

Question 33

Define sexual reproduction

Answer 33

The production of new organisms by the combination of genetic information of two individuals of different sexes.

Question 34

Define somatic cell

Answer 34

Any cell of a living organism other than the reproductive cells.

Question 35

Define substition

Answer 35

The action of replacing someone or something with another person or thing.

Question 36

Define trisomy

Answer 36

A trisomy is a chromosomal condition characterised by an additional chromosome.

Question 37

Define trait

Answer 37

A distinguishing quality or characteristic, typically one belonging to a person.