Genetics

Question 1

Pure bred

Answer 1

An organism that possesses alleles, which are identical, (ie. RR or rr)

Question 2

Homozygous

Answer 2

Purebreds are homozygous. Homozygous means that there are two of the same alleles

Question 3

Heterozygous

Answer 3

Heterozygous organisms have a pair of alleles with different genetic information (ie. Rr)

Question 4

Genotype

Answer 4

The genotype is the genetic make up of an organism or the letters (ie. RR, Rr, or rr)

Question 5

Phenotype

Answer 5

The phenotype is the description of the organisms appearance (which form of the trait appears)

Question 6

Hybrid

Answer 6

An individual formed by mating between unlikely forms. It creates genetic diversity. Traits of both parents show up in offspring

Question 7

F1

Answer 7

The first offspring generation

Question 8

P1

Answer 8

The parental generation

Question 9

F2

Answer 9

The second offspring generation

Question 10

Mendels conclusion

Answer 10

Parents transmit, through gametes, tiny elements (genes) that control traits

Question 11

Alleles

Answer 11

Different forms of one gene that are paired (ie. Rr)

Question 12

Monohybrid

Answer 12

When mixing of genes using only one trait. The hybrid offspring or f1 will only resemble one of the parents traits. The dominant trait

Question 13

Mendel’s 3 laws

Answer 13

1. The principle of dominance - When parents differ in one characteristic, the f1 offspring will only represent one of the parents. NOT a blend of both
2. The principal of segregation - when an f1 offspring reproduces, half will transmit dominant of one parent and the other half recessive of the other parent.
3. The principal of independent assortment - Alleles of different genes assort independently of one another during gamete formation

Question 14

Dihybrid cross

Answer 14

It involves two traits, where each trait still has a dominant and recessive. When you solve the punnet square you have to determine all the possibilities each parent could pass on and then mix it with the other parent’s possibilities. (Ex. If the parent was Ss Bb, they could pass on either SB, Sb, sB, or sb)

Question 15

Co- Dominance (non-dominance)

Answer 15

An exemption to mendel’s monohybrid cross. When two alleles of a gene are equally dominant they combine to produce a new phenotype.
NEITHER TRAIT IS DOMINANT.
Use lowercase since there are no dominant. (C^r- red mixed with C^w- white.
C^r C^r x C^w C^w = C^r C^w)

Question 16

Sex linked traits

Answer 16

All sex linked traits are carried on the x chromosomes. Females have two X chromosomes and males have an X and Y chromosomes.

Question 17

Examples of sex linked traits

Answer 17

-Colour blindness
-Hemophilia -> results from a defect in one of the genes required for normal clotting if blood, and one is recessive
-Duchenne Muscular Dystrophy -> A sudden weakness of skeletal muscles producing paralysis.

Question 18

Multiple Alleles

Answer 18

Several set of genes on homologous chromosomes are capable of affecting inheritance of a particular trait. Several genes where there is an order if dominance. The characteristic is represented by a capital letter, raised small letters represent the trait inherited

Question 19

Chromosomal abnormalities

Answer 19

Means there is an extra or a missing chromosome

Question 20

Karyotype

Answer 20

A photograph of the chromosomes. Its useful to detect defects caused by chromosomal abnormalities.

Question 21

Down syndrome

Answer 21

A chromosomal abnormality caused when there is an extra number 21 chromosome. It can cause, distinctive, physical features such as round eyes, round faces and short, thick fingers. I can also cause a variety of mental deficiencies, and increase the chance of leukemia.

Question 22

Turner Syndrome

Answer 22

There is a missing sex chromosome (x chromosome missing) causing the person to only have 45 chromosomes. This usually only occurs in females and causes nonfunctional ovaries, some physical abnormalities such as broader shoulders and straighter hips, and potential low intelligence.

Question 23

Kline felter’s syndrome

Answer 23

Occurs in males, causing them to have 47 chromosomes. They have an extra X chromosome. (XXY). It can cause men to be tall and have an abnormal arms and legs length. It can also cause them to be sterile, and have low intelligence.

Question 24

Nondisjunction

Answer 24

This is when chromosomes fail to separate properly during meiosis. If non-disjunction happens, there’s usually abnormal development or nothing developments.

Question 25

Barr body’s

Answer 25

They are coiled up and inactive X chromosomes. A barr body is found in Kline felter’s syndrome where the male has an extra X chromosome.

Question 26

Deletion

Answer 26

Piece of a chromosome is missing (result is a lack of information

Question 27

Duplication

Answer 27

Deleted portion of one chromosome becomes attached to its homolog (results in an over abundance of information)

Question 28

Inversion

Answer 28

Selection of a chromosome becomes reversed. (Result is a reversal of the gene order.)

Question 29

Translocation

Answer 29

Fragment of one chromosome becomes attached to a non-homologous chromosome (result is extra or insufficient information)

Question 30

Point mutations

Answer 30

Point mutations is when errors are made in the replication process as DNA is copied for cell division. It can either be a substitution or a deletion. A deletion affects everything else after occurs. The effect of point mutations depends on the purpose of the gene and where on the Protein the change occurs.