Genetics Terms and Definition

Question 1

Heredity

Answer 1

The passing on of physical and mental characteristics from parent to offspring through genetic material, also known as inheritance.

Question 2

Chromosome

Answer 2

Long, thread-like structures composed of DNA and proteins which carry an organism’s genetic information. Located in the nucleus.

Question 3

Gene

Answer 3

The unit of heredity which is transferred from parent to offspring located on a specific part of a chromosome. The specific sequence and code that determines the protein synthesized in the organism.

Question 4

Polygenic Trait

Answer 4

A trait that is influenced by more than one gene. “Many genes.”

Question 5

Pleiotropic

Answer 5

When one gene impacts two or more traits that are seemingly unrelated.

Question 6

Mendelian Trait

Answer 6

A trait that is controlled by a single gene in an organism. (ex. eye color)

Question 7

Allele

Answer 7

One of two or more forms that a gene can take. Different variations for specific characteristics are represented by different alleles or combinations of them.

Question 8

Dominant Allele

Answer 8

An allele that when present, masks any other allele. Only one is needed to show the trait.

Question 9

Recessive Allele

Answer 9

An allele that can be masked by a dominant allele. To show this trait, an organism needs two recessive alleles.

Question 10

Somatic Cell

Answer 10

Any typical body cell that is not a reproductive cell. They are diploid cells.

Question 11

Gamete

Answer 11

A mature sex cell that can unite with another form the opposite sex during reproduction. Sperm in males, egg in females, haploid cells.

Question 12

Diploid

Answer 12

A cell that contains two complete sets of chromosomes, one from each parent.

Question 13

Haploid

Answer 13

A cell that has a single set of chromosomes, or a gamete cell.

Question 14

Heterozygous

Answer 14

When an organism has two different alleles, one dominant and one recessive.

Question 15

Homozygous

Answer 15

When an organism has two same alleles, either both dominant or both recessive.

Question 16

Phenotype

Answer 16

What is physically seen for a trait as a result of the genes present.

Question 17

Genotype

Answer 17

The specific combination of genes present for a trait. Cannot be seen, but the genotype is what causes the phenotype.

Question 18

Sex-linked inheritance

Answer 18

A trait that can be inherited from parent organisms, carried on one of the sex chromosomes.

Question 19

Autosomal Inheritance

Answer 19

A trait passed on that is not carried on one of the sex chromosomes.

Question 20

Mitosis

Answer 20

Division of somatic cells resulting in 2 diploid daughter cells genetically identical to the parent cells.

Question 21

Meiosis

Answer 21

Division of gametes resulting in 4 haploid daughter cells genetically unique from the parents.

Question 22

Chromatin

Answer 22

Material that condenses into chromosomes.

Question 23

Sister chromatid

Answer 23

Two identical copies of a chromosome replicated and paired together.

Question 24

Homologous chromosomes

Answer 24

Two identical pairs of sister chromatids.

Question 25

Nuclear Envelope

Answer 25

The membrane surrounding a cell's nucleus.

Question 26

Spindle Fibers

Answer 26

Protein structures that attach to and separate genetic material in cell division

Question 27

Pure Breeding

Answer 27

An organism that displays two of the same alleles.

Question 28

P Generation

Answer 28

Parental generation

Question 29

F1 Generation

Answer 29

First flial generation, or first set of offspring when the parents are crossed.

Question 30

F2 Generation

Answer 30

Second flial generation, from the crosses of the first flial individuals.

Question 31

Genome

Answer 31

All the genetic information in the chromosomes of an organism.

Question 32

Transcription

Answer 32

The process of making RNA from DNA inside the nucleus since only RNA can make proteins and leave the nucleus.

Question 33

Translation

Answer 33

The process of making proteins (amino acid chains) by reading mRNA codons.

Question 34

Complimentary Pairs

Answer 34

Nitrogenous bases that always pair together in the same way, A with T, and G with C.

Question 35

Substitution Mutation

Answer 35

Replacement of an amino acid with another. This has the ability to change protein function. Natural selection has it, if it is beneficial, the mutation will persist through natural selection.

Question 36

Insertion Mutation

Answer 36

Addition of one or more bases in a DNA sequence. Causes many issues because it messes up everything sequencing after it.

Question 37

Deletion Mutation

Answer 37

A section of bases being deleted or lost during DNA replication. Always alters the protein.

Question 38

Duplication Mutation

Answer 38

Duplicates additional copies of DNA. From unequal crossing over or misaligned chromosome pairs.

Question 39

Inversion Mutation

Answer 39

A portion of the chromosome is rotated 180 degrees. Small ones often go unnoticed. It can lower fertility by producing unbalanced gametes.

Question 40

Translocation Mutation

Answer 40

When portions of two different chromosomes exchange information.

Question 41

Reciprocal Translocation

Answer 41

Exchange of information between non-homologous chromosomes.

Question 42

Robertsonian Translocation

Answer 42

Exchange of information between acrocentric chromosomes.

Question 43

Acrocentric

Answer 43

Where the centromere of a chromosome is closer to one end than the middle.

Question 44

Crossing Over

Answer 44

When chromosomes near each other swap locations of parts of their genetic information. This happens during Prophase 1 of meiosis.

Question 45

Recombination Genotypes

Answer 45

New combinations that arise from crossing over.

Question 46

Parental Genotypes

Answer 46

No crossing over happens.

Question 47

Nondisjunction

Answer 47

Failure for chromosomes to separate during meiosis. Daughter cells have an improper number of chromosomes, often causing chromosomal abnormalities.

Question 48

Interphase

Answer 48

Cell growth stage, where the cell replicates.

Question 49

Prophase

Answer 49

Chromatin condenses into chromosomes and spindle fibers form.

Question 50

Metaphase

Answer 50

Chromosome align at the centre and the spindle fibers attach to chromosomes at their centromere.

Question 51

Anaphase

Answer 51

Spindle fibers pull chromosomes to opposite poles of the cells.

Question 52

Telophase

Answer 52

chromosomes are cornered as new cells begin to form.

Question 53

Cytokinesis

Answer 53

Cytoplasm separates and two cells are formed from the one.

Question 54

Law of Dominance

Answer 54

One allele for a trait will always mask the other unless they are both recessive.

Question 55

Law of Segregation

Answer 55

Two alleles for the same trait will separate during the formation of gametes.

Question 56

Law of Independent Assortment

Answer 56

During gamete formation, genes on separate chromosomes for different traits will assort independently.

Question 57

Incomplete Dominance

Answer 57

Neither trait is dominant and a heterozygous individual will show a mix of both.

Question 58

Codominance

Answer 58

Both traits are equally dominant, seeing both at once

Question 59

Multiple Alleles

Answer 59

More than two options for a trait (example: blood types)

Question 60

Karyotype

Answer 60

A visual representation isolated from a single cell of an individual's complete set of chromosomes, arranged in order of size and shape in pairs.

Question 61

Reading Frame

Answer 61

A chain made up of codons that can be read by the ribosome to make amino acids. It can be altered by the substitution and deletion mutations.

Question 62

Somatic

Answer 62

Cells that are not involved in reproduction.

Question 63

Linkage

Answer 63

The closer the genes are to each other on a chromosome, the more likely they are linked together from parents to offspring.

Question 64

Mode of Inheritance

Answer 64

The pattern in which a gene variant or mutation is inherited and expressed.