Unit 2 - AOS 1

Question 1

Epigenetics

Answer 1

the study of factors that influence the regulation or expression of genes that do not involve changes to the DNA itself.

Question 2

genotype

Answer 2

The genotype of an organism is the set of alleles present in an organism. (written in allele format eg. Aa)

Question 3

phenotype

Answer 3

Phenotype is the physical appearance of an organism – an observable characteristic.
(written with adjective words eg. red hair)

Question 4

allele

Answer 4

An allele is one of two or more versions of DNA sequence (a single base or a segment of bases) at a given genomic location.

Question 5

mutations

Answer 5

A mutation is a change in the DNA sequence of an organism. Mutations can result from errors in DNA replication during cell division.

Question 6

traits

Answer 6

specific characteristics and features of an individual.

Question 7

complete dominance

Answer 7

One allele fully masks the effect of the other, displaying the dominant trait. (A or B bloodtype)

Question 8

incomplete dominance

Answer 8

Heterozygous phenotype is a blend of both alleles, neither fully dominant nor recessive. (AB bloodtype)

Question 9

codominance

Answer 9

Both alleles in a heterozygous genotype are fully expressed, leading to distinct, simultaneous phenotypic traits.

Question 10

tyrosinase (melanin)

Answer 10

an enzyme crucial for melanin production, which determines skin, hair and eye colour.

Question 11

monohybrid crosses

Answer 11

the hybrid of two individuals with homozygous genotypes which result in the opposite phenotype for a certain genetic trait.

Question 12

gene linkage

Answer 12

DNA sequences that are close together on a chromosome to be inherited together during meiosis

Question 13

sex-linkage

Answer 13

Sex linkage applies to genes that are located on the sex chromosomes and its inheritance through members.

Question 14

y-linked

Answer 14

characteristics or traits that are influenced by genes on the Y chromosome only, and therefore is only passed onto males, since they posses a y chromosome.

Question 15

x-linked

Answer 15

characteristics or traits that are influenced by genes on the X chromosome.

Question 16

autosome

Answer 16

any chromosome that is not a sex chromosome.

Question 17

loci

Answer 17

The location of a specific gene on a chromosome

Question 18

carrier

Answer 18

an individual who carries the recessive trait, however it is masked by the dominant allele, therefore they are not affected.

Question 19

crossing over

Answer 19

the exchange of DNA between paired homologous chromosomes in the prophase I of meiosis.

Question 20

dihybrid crosses

Answer 20

A dihybrid cross can investigate two characteristics and its possibilities (eg. skin colour and eye colour)

Question 21

hemizygous

Answer 21

Non-matching pair of chromosomes, with different alleles, shape length, and banding patters (eg. XY chromosomes)

Question 22

homozygous

Answer 22

matching pair of chromosomes, with identical alleles, length and banding patterns.

Question 23

heterozygous

Answer 23

pairs of chromosomes, with the same length and size, however different alleles.

Question 24

mendels law

Answer 24

1. Law of Segregation:
   Parents pass on one version of each gene to their offspring.
2. Law of Independent Assortment:
   Different genes are inherited independently of each other. so one trait does not affect the inheritance of another trait.

Question 25

recombinant gamete

Answer 25

a type of cell that can be created from two different types of cells.

Question 26

genome

Answer 26

The full complement of genes in an individual organism

Question 27

chiasma

Answer 27

The points of attachment where recombination occurs.

Question 28

polygenetic inheritance

Answer 28

the inheritance of an observable trait that is controlled by many genes.

Question 29

monogenetic traits

Answer 29

When there is only one gene controlling a trait, we see discrete variation.

Question 30

environmental factors affecting epigenetics?

Answer 30

Some medicine and drugs (including Alcohol)
pollution
high fat diets
exercise
Chemicals (including nicotine, BPA)

Question 31

meiosis vs mitosis

Answer 31

mitosis is the one division of a cell into two diploid cells. Where as meiosis involves the two divisions of a cell into four new haploid cells.