Biology [1 Mark Question Answer]

Homozygous dominant – RR
Homozygous recessive - rr

Colour-blindness, Thalassaemia, Sickle cell anaemia and Haemophilia.

Haemophilia

X chromosome

The child 1 (daughter) is colour blind

Two sons and three daughters

Father

Haemophilia

Adenine, guanine

Adenosine triphosphate

Colour blindness

Pisum sativam

Heterozygous

Homozygous

Sperm cell

Genes

Retro virus e.g. HIV

Genes

Nucleus

Variation

Heredity

Recessive allele

Homologous chromosomes

Recessive gene

Alleles

Linear

Gene

Homologous Non-sister chromatids

46 chromosomes

23 Pair of chromosomes

Genotype

Haploid

Genetics

Crossing-over : The phenomenon of the exchange of genetic material between two non-sister chromatids of homologous chromosomes during meiosis is called crossing over.

Genotype : Genotype represents the genetic makeup of an individual organism, consisting of the specific combination of alleles or genes.

Recessive character : The character which remains hidden in F1 generation and is expressed in the second generation due to the segregation of alleles.

Dominant Character : The character that is expressed in first generation when any two individuals of contrasting characters breed is called dominant character and the phenomenon is called dominance.

Alleles: Alleles are the alternative forms of the same gene. For example, tallness and dwarfness are the two alternative forms of a gene for height. Similarly, attached ear lobes and free ear lobes are alleles for the type of ear lobes.

Heterosomes : Chromosomes found in reproductive cell and are responsible for the sex of a child, commonly known as sexchromosomes.

Mutation : Mutation signifies a sudden and permanent change in the genetic material (DNA) of an organism, which can result in altered traits or characteristics.

Linkage : Linkage refers to the phenomenon where two or more genes are located on the same chromosome and tend to be inherited together, during meiosis.