Genetics

Question 1

Define gene?

Answer 1

Is a unit if genetic information that gives instructions on how to make protein and is made of DNA

Question 2

What is genetics?

Answer 2

It is the study of hereditary and variation , it involves I hesitance of physical and biological characteristics from the parent to offspring by the help of genes and alleles

Question 3

What is DNA?

Answer 3

DNA stores all genetics information in a cell , specific segments of DNA called genes encode for the production of protein

Question 4

What is chromosome?

Answer 4

Chromosomes are very long, coiled pieces of DNA, which can be easily copied and pass on genetic information during cell division.

Question 5

What is genotype?

Answer 5

Genotype is the combination of alleles an organism has for a particular trait or for all traits.

Question 6

What is the phenotype?

Answer 6

Phenontype is the observable physical, or biochemical characteristics that organism has, which are influenced by both its genotype and environment.

Question 7

What is Dominant trait / allele ?

Answer 7

Fully expressed in the genotype and phenotype of an organism because the dominant allele masks the effect of recessive allele in the genotype

Question 8

What is recessive trait / allele?

Answer 8

Recessive allele is partially expressed or not expressed in the genotype or phenotype of an organism. It is only expressed if it is homozygous recessive

Question 9

What is homozygous?

Answer 9

Is the true breeding whereby there are 2 identical alleles for a particular trait and it has only has dominant or recessive allele (not both at once) and it produces 1 type of gamete

Question 10

What is heterozygous?

Answer 10

Heterozygous is where an organism has two different alleles for a particular gene — one dominant and one recessive and it produces 2 types of gamete

Question 11

How many type of gametes does homozygous produce?

Answer 11

1 types

Question 12

How many type of gametes does heterozygous produce?

Answer 12

2 type

Question 13

List 3 difference between homozygous and heterozygous

Answer 13

Homozygous
- Heterozygous means an organism has two different alleles for a particular gene — one dominant and one recessive.

• it produces only 1 type of gamete
• both the alleles are similar eg RR rr

WHEREAS

heterozygous

-Heterozygous means an organism has two different alleles for a particular gene — one dominant and one recessive.

• produces 2 type of gamete
• alleles are not similar eg Rr

Question 14

What is haploid cell?

Answer 14

A haploid cell is a cell that contains only one chromosome from each homologous pair, meaning it has a single set of chromosomes and only one allele for each gene. Examples include gametes such as sperm and egg cells, and pollen grains.

Question 15

What is diploid cell?

Answer 15

A diploid cell is a cell that contains full sets of homologous chromosomes, one set inherited from each parent. It has two alleles for each gene, one from each parent, which together code for each trait. Examples of diploid cells include somatic cells, such as liver and muscle cells.

Question 16

What is Homologous Pair?

Answer 16

Homologous refers to chromosomes that are similar in size, shape, and carry the same genes, with one chromosome coming from each parent.

Question 17

What is Homologous Pair?

Answer 17

Homologous refers to chromosomes that are similar in size, shape, and carry the same genes, with one chromosome coming from each parent.

Question 18

What is genetic continuity?

Answer 18

Genetic continuity refers to the maintenance of the number and type of genes in daughter cells, inherited from the parent cell, ensuring that genetic information is preserved for the survival and functioning of the organism

Question 19

Who is the father of genetics?

Answer 19

Gregor Mendel

Question 20

What is Mendels first law?

Answer 20

States Allele pairs segregate randomly during gamete formation and unite during fertilization to form the genotype of the offspring.”

Question 21

What is non-segregation?

Answer 21

This is when allele Pais are unable to separate during meiosis one which results in genetic disorder

Question 22

State the law of Assortment

Answer 22

The Law of Independent Assortment states that genes for different traits are passed on independently of one another from parent to offspring during gamete formation. This process occurs during metaphase I of meiosis, where homologous chromosomes are randomly arranged and separated, ensuring that offspring receive a mix of chromosomes from both parents.

Question 23

What is crossing over?

Answer 23

Crossing over is the process where non-sister chromatids of homologous chromosomes exchange genetic material at points called chiasma during prophase I of meiosis. This leads to new allele combinations and increases genetic variation in gametes.

Question 24

What is the point known as where cross over takes place?

Answer 24

Chiasma

Question 26

Crossing over is also known as ?

Answer 26

Gene recombination

Question 27

What is random fertilisation?

Answer 27

Is where fertilisation between make and female occurs randomly which leads to genetic variation due to different combination of genes from male and female gamete

Question 28

What are the 3 advantage of random fertilisation?

Answer 28

1. Random fertilization increases genetic variation amongst population because any sperm can join with any egg, making each offspring unique. 2. It reduces the risk of genetic diseases being passed on often, because of the mixing of different genes. 3. It increases chances of survival for the species by producing offspring with different traits to survive the environmental changes

Question 29

What are 3 disadvantages of random fertilisation?

Answer 29

1.Low chance of fertilization – Since sperm and eggs are released into the environment, they may not meet, reducing the chances of successful fertilization. 2.High risk of predation – Sperm and eggs released externally can be eaten by predators, decreasing the number available for fertilization. 3. No control over genetic outcomes – Parents cannot control which traits the offspring will inherit, which may lead to unfavorable combinations.

Question 30

What is complete dominance ?

Answer 30

Is where dominant allele is fully expressed , the presence of dominant allele masks the effect of recessive allele Example: Red flower (R) + white flower (r) = all red flowers (Rr)

Question 31

What is incomplete dominance?

Answer 31

Is where dominant allele partially masks the effect of recessive allele, both of them are partially expressed Example: Red flower (R) + white flower (r) = pink flowers (Rr)

Question 32

What is co-dominance?

Answer 32

Is a heterozygous condition where both alleles are expressed in phenotype ,neither being dominant or recessive to each other In cattle, a red cow (RR) crossed with a white cow (WW) results in a roan cow (RW), where both red and white fur are equally expressed.

Question 33

What is sex linked trait?

Answer 33

Genes that are carried by either the X or Y sex chromosomes are said to be sex-linked.

Question 34

List 2 most well known sex linked conditions?

Answer 34

Haemophilia and colour blindness

Question 35

The sex linked conditions are dominant or recessive in nature?

Answer 35

Recessive

Question 36

What chromosome combination do woman have?

Answer 36

XX

Question 37

What chromosome combination do man have?

Answer 37

XY

Question 39

Why aren’t woman’s mostly affected by sex linked conditions?

Answer 39

Because the X chromosome is the carrier of sex linked conditions there are 2 X chromosomes and if one X chromosome has a condition , the other one masks the effect of it

Question 40

Why are mens mostly affected by sex linked conditions

Answer 40

Because x is the carrier of sex linked condition If the gene on their X chromosome has sex linked condition , they don’t have another X to cover up the problem unlike woman where they have 2 X chromosome that masks the effect of another x chromosome

Question 41

What is monohybrid cross?

Answer 41

A monohybrid cross is a cross between two pure-breeding parents showing alternate forms of one trait

Question 42

What is dihybrid?

Answer 42

A dihybrid cross occurs between parents, which are true breeding for contrasting form of two traits.

Question 43

What is karyotype?

Answer 43

A karyotype is a printout of chromosomes in a cell, arranged in pairs and in order of size. It is used to study chromosome number and structure, and to detect genetic disorders and sex of baby