Reproduction, DNA, Genetics, and Mutations Flashcards

Flashcards covering key vocabulary related to sexual and asexual reproduction, human reproductive systems, DNA, genetics, and mutations.

Sexual Reproduction

Involves the union of sex cells (gametes) to form a zygote (a single fertilised cell).

Gametes

A sex cell (sperm or ovum) which is a haploid reproductive cell of an organism.

Zygote

The diploid, single cell that is formed at fertilisation.

Gonads

An organ (testis or ovary) which produces sex cells.

Asexual Reproduction

The production of offspring without involving sex cells (gametes).

Menstrual Cycle

A recurring cycle of hormonal changes in females, averaging 28 days, involving menstruation and ovulation.

Menarche

The first menstrual cycle in females.

Menopause

The cessation of menstruation in females.

Ovulation

The process of the ovum being released from a follicle in the ovary in the middle of the menstrual cycle.

FSH (Follicle Stimulating Hormone)

A hormone produced by the pituitary gland that promotes follicle development and ovum maturation.

LH (Luteinising Hormone)

A hormone from the pituitary gland that triggers ovulation.

Oestrogen

A hormone produced by ovarian follicles that thickens the uterine lining.

Progesterone

A hormone secreted by the corpus luteum that maintains the uterine lining.

Foetus

An embryo after 8 weeks of development.

DNA (Deoxyribonucleic Acid)

A complex molecule containing the genetic blueprint for an organism.

Nucleotide

The basic building block of DNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

Nitrogenous Bases

Adenine (A), Thymine (T), Guanine (G), and Cytosine (C), which form the genetic code in DNA.

RNA (Ribonucleic Acid)

A nucleic acid that plays various roles in genetic processes, including protein synthesis.

Chromosomes

Tightly coiled DNA structures found in the nucleus of cells.

Autosomes

Non-sex chromosomes.

Sex Chromosomes

Chromosomes that determine biological sex (XX for females, XY for males).

Centromere

The region of a chromosome where sister chromatids are joined.

Genes

DNA sequences on chromosomes that code for proteins.

Alleles

Alternative versions of a gene.

Karyogram (Karyotype)

An image of chromosomes arranged in homologous pairs based on size, centromere position, and banding patterns.

DNA Replication

The process of duplicating DNA before cell division.

Somatic Cells

Body cells that contain chromosomes in pairs (diploid).

Diploid (2n)

Having two sets of chromosomes.

Haploid (n)

Having one set of chromosomes.

Mitosis

Nuclear division that produces diploid body cells for growth, repair, and replacement.

Meiosis

Nuclear division that produces haploid sex cells in the gonads for reproduction.

Cytokinesis

The division of the cytoplasm and whole cell into two new diploid daughter cells.

Inheritance

The passing of traits from one generation to the next.

Genetics

The study of inheritance.

Complete Dominance

A type of inheritance where a dominant allele completely masks a recessive allele.

Genotype

The symbolic representation of the alleles possessed for a particular trait.

Homozygous

Both copies of an allele are the same.

Heterozygous

Both copies of an allele are different.

Phenotype

The visible affect of the genotype possessed.

Pedigrees

Illustrations of inheritance patterns within families to determine if a trait is dominant or recessive.

Autosomal Inheritance

Inheritance of traits located on autosomes (non-sex chromosomes).

Sex-Linked Inheritance

Inheritance of traits via sex chromosomes (X or Y).

Punnett Square

A grid used to predict genotypes and phenotypes in genetic crosses.

Incomplete Dominance

A heterozygous individual shows a blended phenotype.

Codominance

Both alleles are fully expressed in a heterozygous individual.

Protein Synthesis

The process of constructing proteins based on genetic instructions carried by DNA and RNA.

Central Dogma of Biology

DNA → RNA → Protein.

mRNA (Messenger RNA)

Transcribes genetic code from DNA and carries it to ribosomes.

rRNA (Ribosomal RNA)

Forms the core of ribosome's structure and facilitates protein synthesis.

tRNA (Transfer RNA)

Brings amino acids to ribosomes during translation to form proteins.

Transcription

The process of copying DNA into mRNA.

Translation

The process of decoding mRNA to synthesize proteins.

Mutations

A change to the DNA sequence in genes and chromosomes.

Mutagens

Environmental agents that cause mutations.

Gene Mutations (Point Mutations)

Small-scale changes in the DNA base sequences within genes.

Chromosome Mutations

Larger-scale mutations that include whole extra or missing chromosomes or significant deletions or translocations of chromosome sections.

Substitution

A gene mutation where one base is replaced by another.

Inversion

A gene mutation where a sequence of bases is flipped.

Insertion

A gene mutation where additional bases are added, causing a frameshift.

Deletion

A gene mutation where bases are removed, causing a frameshift.

Aneuploidy

An abnormal number of chromosomes in a cell.

Monosomy

The presence of only one copy of a chromosome instead of the usual two.

Trisomy

The presence of an extra chromosome, leading to three copies.

Non-disjunction

The failure of chromosome pairs to separate properly during cell division.