Reproduction & Inheritance in Biology

A collection of flashcards designed to reinforce key concepts and definitions from the lecture notes on reproduction and inheritance in biology.

What is a gene locus?

The position of a gene on a chromosome.

What is the primary function of a gene?

To code for a single polypeptide or protein.

What are alleles?

Different forms of a gene that occupy the same locus on a chromosome.

Define gene linkage.

Gene loci are said to be linked if they are located on the same chromosome.

How are autosomal linkage and sex linkage different?

Autosomal linkage occurs on autosomes, while sex linkage occurs on sex chromosomes.

What are the sex chromosomes in humans?

X and Y chromosomes.

What characteristic describes male chromosomes in terms of sex linkage?

Males have only one copy of the X chromosome.

What is a carrier in genetic terms?

A female with one recessive allele that does not show symptoms of a recessive condition but can pass it on.

How can the presence of sex linkage be identified?

Using pedigree diagrams and Punnett squares.

What does meiosis produce?

Gametes that are genetically different from each other.

What are the two main stages of meiosis?

Meiosis I and Meiosis II.

What is independent assortment?

The random alignment of homologous chromosomes during meiosis, creating genetic diversity.

What is crossing over?

The exchange of alleles between non-sister chromatids during prophase I of meiosis.

What do gametes fuse to form?

A zygote.

What are mammalian gametes specialized for?

To increase the chances of fertilisation and successful embryonic development.

What occurs during fertilisation in mammals?

The fusion of male and female gamete nuclei.

What is double fertilisation in flowering plants?

A process where one male nucleus fuses with an egg cell and another with polar nuclei to form endosperm.

What is the purpose of the acrosome reaction?

To digest a path through the egg cell's zona pellucida during fertilisation.

What is the mitotic index formula?

Mitotic index = number of cells with visible chromosomes ÷ total number of cells.

What characterizes totipotent stem cells?

They can differentiate into any cell type, including placental cells.

Define pluripotent stem cells.

Stem cells that can differentiate into any cell type in an embryo but not into placental cells.

What is differential gene expression?

The activation of specific genes in stem cells that leads to cell specialization.

What is epigenetics?

The study of gene expression control through mechanisms other than changes to the DNA sequence.

What is the lac operon?

A group of genes in bacteria that are controlled together for lactose metabolism.

What effect does DNA methylation have on gene expression?

It suppresses transcription by inhibiting enzyme binding.

How can alternative splicing affect protein diversity?

It allows for different combinations of exons to produce various proteins from a single gene.