genetics

Question 1

what are genetics

Answer 1

Genetics is the study of heredity, inheritance and characteristics.

Question 2

DNA

Answer 2

deoxyribonnucleic acid

Question 3

definition of dna

Answer 3

DNA is a large molecule shaped as a double helix that stretches up to 2 metres that contains genetic information and instructions for building proteins.

Question 4

What is DNA made of

Answer 4

DNA is made of chemical building blocks called nucleotides.

Question 5

what is a nucleotide

Answer 5

a phosphate group

Question 6

definition of geonome

Answer 6

A genome is a complete set of DNA in an organism.

Question 7

definition of gene

Answer 7

A gene is a sequence/section of DNA that codes for a specific trait and contains genetic information for building a specific protein.

Question 8

definition of a chromosome

Answer 8

Chromosomes are tightly condensed and coiled DNA that are only visible during cell division and keep the DNA condensed with the help of proteins called histones.

Question 9

structure of chromosomes

Answer 9

A chromosome has a centromere that attaches chromatids, sister chromatids, parm (short arm structure) and qarm (long arm structure) and DNA structure.

Question 10

Types and number of Chromosomes in human body

Answer 10

There are 22 pairs of autosomes in human body and 1 pair of sex chromosomes. Altogether, there are 46 chromosomes and 23 pairs of chromosomes.

Question 11

Homologous

Answer 11

Homologous chromosomes are those that have the same size, same location of centromere and same stained banding patterns

Question 12

non-homologous

Answer 12

different

Question 13

karyotype

Answer 13

A karyotype is an image of a complete set of chromosomes.

Question 14

Term for incorrect distribution of Chromosomes

Answer 14

Incorrect distribution of chromosomes is called non-disjunction. The two types of non-disjunction are trisomy and monosomy.

Question 15

cell division

Answer 15

Cell division is the vital process of replicated chromosomes in an original cell being divided to form new cells.

Question 16

somatic cells

Answer 16

Somatic/body cells are diploid cells (two copies of each chromosome) that are produced by mitosis and have the same kind and number of chromosomes.

Question 17

gamete cells

Answer 17

Gametes/sex cells (sperm and egg/ova) are haploid cells (one copy of each chromosome) that are produced via meiosis and contain DNA that can be passed to offspring.

Question 18

fertilisation

Answer 18

This is the process of the fusion of male (sperm) and female (egg) gametes.

Question 19

zygote

Answer 19

a fertilised egg

Question 20

embryo

Answer 20

an organism in early stages of development.

Question 21

Cell cycle definition

Answer 21

series of events that cells go through as they grow and divide.

Question 22

mitosis

Answer 22

is the process of a parent cell dividing to form two genetically identical daughter cells. It is also the division of a cell into 2 nuclei with the same kind and number of chromosomes.

Question 23

interphase

Answer 23

when the cell develops, grows, carries out activities and replicates DNA.

Question 24

Prophase

Answer 24

chromosomes condense, nuclear envelope disappears and spindle fibres form.

Question 25

metaphase

Answer 25

spindle fibres connect to chromosomes and they line up at the equatorial plate in the middle.

Question 26

anaphase

Answer 26

Spindle fibres pull apart and divide chromatids to opposite poles.

Question 27

telophase

Answer 27

Spindle fibres disappear, 2 nuclei and nuclear envelope form and chromosomes uncoil back into DNA.

Question 28

cytokenesis

Answer 28

Division of cytoplasm and other organelles.

Question 29

meiosis

Answer 29

the process of cell division in which the parents cell divides into four genetically different haploid daughter cells.

Question 30

Prophase 1

Answer 30

The nuclear membrane disappears, spindle fibres forms and chromosomes coil. Then, the chromosomes find their homologous pair and crossing over (the exchange of genes between homologous chromosomes) occurs to create genetic variation.

Question 31

Metaphase 1

Answer 31

The spindle fibres connect to the homol0gous chromosomes and they line up along the equatorial plate in the middle.

Question 32

anaphase 1

Answer 32

The chromosomes separate by the spindle fibres to each end of the cell.

Question 33

telophase 1

Answer 33

The nuclear membrane forms, 2 nuclei are visible in two cells and the spindle fibres disappear.

Question 34

cytokenesis 1

Answer 34

The cytoplasm splits into two new cells.

Question 35

metaphase 2

Answer 35

The spindle fibres connect to the chromosome and they line up at the equatorial plate in the middle.

Question 35

prophase 2

Answer 35

The nuclear membrane disappears and spindle fibres reform.

Question 36

anaphase 2

Answer 36

The chromosomes are divided into chromatids and split to both ends of the cells.

Question 37

telophase 2

Answer 37

The nuclear membrane reforms around chromatids, spindle fibres disappear, and 4 nuclei are present in four new cells.

Question 38

cytokinesis 2

Answer 38

the cytoplasm splits to form four haploid daughter cells.

Question 39

mutations

Answer 39

Mutations are mistakes that occur during the DNA sequence before or during mitosis and meiosis. Mutations in mitosis can lead to tumours and cancer while mutations in meiosis can lead to inherited mutations.
While some mutations are harmful, many are a beneficial source of variation within a species.

Question 40

allele

Answer 40

Alleles are the alternative forms/possibilities of a gene that code for the different variations of a specific trait.
Alleles are either dominant and Recessive alleles that are either homozygous or heterozygous.

Question 41

genotype

Answer 41

a genotype is the gene composition / allele combination for a specific trait.

Question 42

phenotype

Answer 42

a phenotype are the observable physical, biochemical or behavioural characteristics of a specific trait determined by the genotype and environmental influences.

Question 43

dominate allele

Answer 43

a dominant allele is represented by a capital letter and is always expressed in the phenotype of an individual, even if one copy is present.

Question 44

ressesive allele

Answer 44

a recessive allele is represented by a lower case letter and is only expressed if two copies are present and no dominant allele is present, or else is masked by the dominant allele.

Question 45

type of dominace

Answer 45

Complete dominance (recessive allele is masked)
Codominance (two alleles equally expressed in phenotype)
Incomplete/partial dominance (blending of two alleles)

Question 46

pedigree chart

Answer 46

a pedigree chart is a chart of genetic history in a family over generations.
Marriage line, Line of descent, Sibling line, Twins, Female, Male, Affected/Unaffected, Carriers and Generation number (roman numerals).

Question 47

Autosomal dominant

Answer 47

If both parents are affected and have an unaffected offspring, the trait has to be dominant.
All affected individuals must have at least one affected parent.
This will not skip a generation.
If both parents are unaffected, all offspring’s must be unaffected too.

Question 48

Characteristics of Autosomal recessive disease:

Answer 48

If both parents are unaffected and an offspring is affected, the trait has to be recessive.
If both parents show a trait, all offspring must too.

Question 49

Characteristics of X-linked dominant disease:

Answer 49

If a male father shows a trait, so must all daughters and well as the male father’s mother.
An unaffected mother cannot have affected sons or an affected father.
These tend to be more common in females (is not sufficient evidence though).

Question 50

Characteristics of X-linked recessive disease:

Answer 50

If a mother shows a trait so too must all sons as well as the affected mother’s father.
An unaffected mother can have affected sons if she is a heterozygous carrier.
These tend to be more common in males (is not sufficient evidence though).