Biology Lecture: Meiosis, Reproduction, Metabolism, and Molecular Genetics

Vocabulary flashcards covering meiosis, chromosome terminology, enzyme kinetics, photosynthesis, cellular respiration, and DNA structural components based on the lecture.

Meiosis

A special type of cell division occurring only in the testes and ovaries that produces four haploid gametes (egg and sperm) with half the original chromosome number.

Mitosis

The process of cell division by which body cells reproduce to make two genetically identical daughter cells.

Diploid number ($2n$)

The condition of having two sets of chromosomes, one from each parent; in humans, this number is $46$ (two sets of $23$ chromosomes).

Haploid number ($n$)

The condition of having a single set of chromosomes, characteristic of gametes; in humans, this number is $23$.

Karyotype

A complete set of all chromosomes displayed by size and pattern.

Homologous chromosomes

Chromosome pairs that share a similar length, identical centromere position, and genes controlling the same inherited traits, with one inherited maternally and one paternally.

Zygote

A fertilized diploid egg formed when a haploid sperm and haploid egg unite during fertilization.

Synapsis

The pairing up of homologous chromosomes that occurs during prophase I of meiosis.

Crossing over

A process occurring in prophase I where homologous chromosomes exchange genetic information through the breaking and rejoining of DNA molecules.

Recombinant chromosomes

Chromosomes resulting from synapsis and crossing over that carry exchanged genetic material and are no longer identical to their sister chromatids.

Independent assortment

A mechanism contributing to genetic variation where the separation and distribution of each homolog to a side of the dividing cell is completely random and independent of other chromosomes.

Cytokinesis

The physical division of the cytoplasm during cell division.

Enzyme

A biological protein catalyst that speeds up chemical reactions without being consumed in the process.

Activation energy

The initial amount of energy required to start a chemical reaction, which is lowered by the presence of an enzyme.

Competitive inhibitor

A reversible inhibitor that competes directly with the substrate to bind to the enzyme's active site.

Noncompetitive inhibitor

A reversible inhibitor that binds to an enzyme at a location other than the active site, causing a reduction in enzyme activity.

Anabolic process

A metabolic pathway that builds complex molecules from simpler ones, such as photosynthesis building glucose molecules.

Catabolic process

A metabolic pathway that breaks down complex molecules to release energy, such as cellular respiration breaking down glucose.

Thylakoid

The specific structure inside the chloroplast where the light reactions of photosynthesis take place.

Stroma

The fluid-filled space within the chloroplast where the Calvin cycle takes place.

Glycolysis

The initial stage of cellular respiration that occurs in the cytosol, breaking down glucose to produce a small amount of ATP without requiring oxygen.

Oxidative phosphorylation

The stage of cellular respiration occurring in the mitochondria where oxygen acts as the final electron acceptor to generate the largest yield of ATP.

Antiparallel

The structural arrangement of the two complementary strands of DNA, where one strand runs in the $5'$ to $3'$ direction and the other runs in the $3'$ to $5'$ direction.

Five prime ($5'$) end

The terminal end of a DNA strand that bears a phosphate group.

Three prime ($3'$) end

The terminal end of a DNA strand that bears a hydroxyl group.