Unit 3 List 2 DNA & Heredity

Question 1

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

Centromere

Answer 2

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

Question 3

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

Chromosome

Answer 4

Chromosomes are threadlike structures made of protein and a single molecule of DNA that serve to carry the genomic information from cell to cell.

Question 5

Codon (chart)

Answer 5

The RNA codon chart helps us to identify which codons specify which amino acids.

Question 6

Crossing Over

Answer 6

Crossing over is a cellular process that happens during meiosis when chromosomes of the same type are lined up.

Question 7

Daughter Cell

Answer 7

The daughter cell definition is the cells that are formed after cell division.

Question 8

Deletion

Answer 8

A deletion changes the DNA sequence by removing at least one nucleotide in a gene. Small deletions remove one or a few nucleotides within a gene, while larger deletions can remove an entire gene or several neighboring genes. The deleted DNA may alter the function of the affected protein or proteins.

Question 9

Diploid

Answer 9

of a cell or nucleus) containing two complete sets of chromosomes, one from each parent.

Question 10

DNA

Answer 10

Deoxyribonucleic acid (abbreviated DNA) is the molecule that carries genetic information for the development and functioning of an organism.

Question 11

Fertilization

Answer 11

Fertilization is a complex multi-step process that is complete in 24 hours. The sperm from a male meets an ovum from a female and forms a zygote; this is the point in which pregnancy begins and leads to a 280-day journey for a female. There are two ways to track this process, and they differ by the day counting begins.

Question 12

Frameshift

Answer 12

A frameshift mutation is a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read. A DNA sequence is a chain of many smaller molecules called nucleotides.

Question 13

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

Gene

Answer 14

(in technical use) a distinct sequence of nucleotides forming part of a chromosome, the order of which determines the order of monomers in a polypeptide or nucleic acid molecule which a cell (or virus) may synthesize.

Question 15

Gene Mutation

Answer 15

A gene mutation (myoo-TAY-shun) is a change in one or more genes. Some mutations can lead to genetic disorders or illnesses.

Question 16

Genetic Code

Answer 16

the sequence of nucleotides in deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) that determines the amino acid sequence of proteins. Though the linear sequence of nucleotides in DNA contains the information for protein sequences, proteins are not made directly from DNA

Question 17

Genetic Variation

Answer 17

Genetic variation is the presence of differences in sequences of genes between individual organisms of a species. It enables natural selection, one of the primary forces driving the evolution of life.

Question 18

Haploid

Answer 18

Haploid refers to the presence of a single set of chromosomes in an organism’s cells. Sexually reproducing organisms are diploid (having two sets of chromosomes, one from each parent).

Question 19

Homologous Chromosome

Answer 19

Homologous chromosomes are made up of chromosome pairs of approximately the same length, centromere position, and staining pattern, for genes with the same corresponding loci. One homologous chromosome is inherited from the organism’s mother; the other is inherited from the organism’s father.

Question 20

Independent Assortment

Answer 20

The Principle of Independent Assortment describes how different genes independently separate from one another when reproductive cells develop. Independent assortment of genes and their corresponding traits was first observed by Gregor Mendel in 1865 during his studies of genetics in pea plants.

Question 21

Insertion

Answer 21

An insertion, as related to genomics, is a type of mutation that involves the addition of one or more nucleotides into a segment of DNA.

Question 22

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). In humans, body (or somatic) cells are diploid, containing two sets of chromosomes (one from each parent).

Question 23

Meiosis 1

Answer 23

Meiosis I is a type of cell division unique to germ cells, while meiosis II is similar to mitosis. Meiosis I, the first meiotic division, begins with prophase I. During prophase I, the complex of DNA and protein known as chromatin condenses to form chromosomes.

Question 24

Meiosis 2

Answer 24

During meiosis II, the sister chromatids within the two daughter cells separate, forming four new haploid gametes. The mechanics of meiosis II is similar to mitosis, except that each dividing cell has only one set of homologous chromosomes.

Question 25

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. When cells have one chromosome from a pair plus a portion of the second chromosome, this is referred to as partial monosomy.

Question 26

Mutagen

Answer 26

Anything that causes a mutation (a change in the DNA of a cell). DNA changes caused by mutagens may harm cells and cause certain diseases, such as cancer. Examples of mutagens include radioactive substances, x-rays, ultraviolet radiation, and certain chemicals.

Question 27

Mutation

Answer 27

Any change in the DNA sequence of a cell. Mutations may be caused by mistakes during cell division, or they may be caused by exposure to DNA-damaging agents in the environment. Mutations can be harmful, beneficial, or have no effect.

Question 28

Nondisjuction

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. This probably occurs most commonly in meiosis, but it may occur in mitosis to produce a mosaic individual.

Question 29

Offspring

Answer 29

In biology, offspring are the young creation of living organisms, produced either by sexual or asexual reproduction. Collective offspring may be known as a brood or progeny.

Question 30

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

Point Mutation

Answer 31

A point mutation occurs in a genome when a single base pair is added, deleted or changed. While most point mutations are benign, they can also have various functional consequences, including changes in gene expression or alterations in encoded proteins.

Question 32

Replication

Answer 32

DNA replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules.

Question 33

Sexual Reproduction

Answer 33

sexual reproduction, the production of new organisms by the combination of genetic information of two individuals of different sexes. In most species the genetic information is carried on chromosomes in the nucleus of reproductive cells called gametes, which then fuse to form a diploid zygote.

Question 34

Somatic Cell

Answer 34

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

Question 35

Substitution

Answer 35

Substitution, as related to genomics, is a type of mutation in which one nucleotide is replaced by a different nucleotide. The term can also refer to the replacement of one amino acid in a protein with a different amino acid.

Question 36

Trisomy

Answer 36

A trisomy is a chromosomal condition characterised by an additional chromosome. A person with a trisomy has 47 chromosomes instead of 46. Down syndrome, Edward syndrome and Patau syndrome are the most common forms of trisomy.

Question 37

Trait

Answer 37

A trait, as related to genetics, is a specific characteristic of an individual. Traits can be determined by genes, environmental factors or by a combination of both. Traits can be qualitative (such as eye color) or quantitative (such as height or blood pressure).