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 fusion of sex cells (gametes) to form a fertilized zygote, resulting in genetic diversity.

Gametes

Sex cells (sperm and ova/ovules and pollen) involved in sexual reproduction.

Zygote

The cell formed by the fusion of two gametes; the first cell of a new organism.

Gonads

Organs that produce gametes (testes in males, ovaries in females).

Asexual Reproduction

A process where offspring are produced without gametes, resulting in genetically identical clones of the parent.

Binary Fission

A type of asexual reproduction in single-celled organisms where a parent splits into two.

Fragmentation

A type of asexual reproduction where new individuals develop from body parts.

Vegetative Propagation

A type of asexual reproduction in plants where new growth arises from cuttings or runners.

Budding

A type of asexual reproduction where small buds grow and detach to form new organisms.

Spore Formation

A type of asexual reproduction where asexual spores disperse and grow into new organisms.

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 release of an ovum from the ovary.

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.

Placenta

An organ that forms during pregnancy, allowing exchange of oxygen, nutrients, and waste between mother and embryo.

Foetus

An embryo after 8 weeks of development.

Amniotic Sac

A fluid-filled sac that protects the foetus.

Gestation

The period of development inside the uterus from conception to birth (about nine months in humans).

Fraternal Twins

Twins resulting from two different eggs fertilized by two different sperm.

Identical Twins

Twins resulting from one fertilized egg splitting into two.

Sexually Transmitted Diseases (STDs/STIs)

Infections caused by bacteria or viruses transmitted through sexual contact.

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.

Histones

Proteins that package DNA into chromosomes.

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.

Karyotyping

The process of arranging chromosomes in a standard sequence to detect mutations or abnormalities.

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.

Helicase

An enzyme that separates the two strands of DNA during replication.

DNA Polymerase

An enzyme that assists in the formation of new DNA strands during replication.

Somatic Cells

Body cells that contain chromosomes in pairs (diploid).

Gametes

Sex cells (sperm and ova) that contain only one set of chromosomes (haploid).

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.

Prophase

The first phase of mitosis, during which the nuclear membrane disintegrates and spindle fibers form.

Metaphase

The phase of mitosis during which chromosomes align at the equator of the cell.

Anaphase

The phase of mitosis during which chromatids separate and move toward opposite poles.

Telophase

The phase of mitosis during which new nuclear membranes form around each nucleus.

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.

Locus

The location of a gene on a chromosome.

Complete Dominance

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

Genotype

The genetic makeup of an individual (e.g., BB, Bb, or bb).

Homozygous

Having identical alleles for a trait (BB or bb).

Heterozygous

Having different alleles for a trait (Bb).

Phenotype

The observable trait expressed by an individual.

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.

Monohybrid Cross

The inheritance of one gene (trait) at a time.

Dihybrid Cross

The inheritance of two genes at a time.

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

Changes in the DNA sequence of 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.

Karyotyping

A diagnostic test that produces a karyogram to visualize and analyze chromosome structure.

Turner Syndrome

A genetic disorder in which a female has only one X chromosome (Monosomy X).

Down Syndrome

A genetic disorder in which a person has an extra chromosome 21 (Trisomy 21).