Meiosis & Reproduction

These flashcards cover key concepts related to meiosis and reproduction, including processes, definitions, and differences between asexual and sexual reproduction.

Meiosis

A type of cell division that reduces the chromosome number by half, resulting in four haploid cells.

Haploid

Cells that contain a single set of chromosomes (n).

Diploid

Cells that contain two sets of chromosomes (2n).

Homologous chromosomes

Chromosomes that have the same sequence of genes and the same structure.

Sister chromatids

Identical copies of a chromosome, connected by a centromere.

Centromere

The region where two sister chromatids are joined together.

Interphase

The stage of the cell cycle when a cell is not dividing, and chromosomes are duplicated.

Prophase 1

The first stage of Meiosis 1 where chromosomes condense and the nuclear envelope disappears.

Synapsis

The process where homologous chromosomes bind together during Prophase 1.

Tetrad

A structure containing four chromatids formed during synapsis.

Chiasmata

X-shaped regions where crossing over occurs between non-sister chromatids.

Crossing over

The exchange of genetic material between homologous chromosomes.

Metaphase 1

The stage where tetrads line up at the metaphase plate.

Anaphase 1

The stage in Meiosis 1 where homologous chromosomes are pulled apart.

Telophase 1

The stage where cells begin to divide and nuclear envelopes form around each nucleus.

Cytokinesis

The division of cytoplasm that follows telophase.

Meiosis 2

The second division in meiosis where sister chromatids are separated.

Prophase 2

The stage where sister chromatids condense and the nuclear envelope disappears.

Metaphase 2

The stage where chromosomes line up at the metaphase plate.

Anaphase 2

The stage where sister chromatids are pulled apart by microtubules.

Telophase 2

The final stage where chromosomes arrive at the poles and decondense.

Asexual reproduction

A form of reproduction involving a single parent that results in genetically identical offspring.

Sexual reproduction

A form of reproduction involving two parents that produces gametes and leads to genetic variation.

Gametes

Reproductive cells (sex cells) that contain half the number of chromosomes.

Egg cell

Female gamete, where 22 autosomes + X sex chromosome combine.

Sperm cell

Male gamete, where 22 autosomes + X or Y sex chromosome combine.

Life cycle

The series of stages from the beginning of an organism's life to the production of its own offspring.

Somatic cell

Any cell of a living organism other than the reproductive cells.

Autosomes

The 22 pairs of chromosomes that do not determine sex.

Sex chromosomes

The chromosomes that determine the sex of an organism; X and Y.

Alternation of generations

A life cycle type where diploid and haploid stages alternate.

Microtubules

Cytoskeletal fibers that pull chromosomes to the poles during cell division.

Nuclear envelope

The double membrane surrounding the nucleus.

Cleavage furrow

The indentation that begins the process of cytokinesis in animal cells.

Synaptonemal complex

A structure that forms between homologous chromosomes during synapsis.

Chromosome condensing

The process by which chromatin becomes tightly coiled and visible during cell division.

Budding

An asexual reproduction method where a new organism develops from an outgrowth.

Binary fission

A form of asexual reproduction where a cell divides into two roughly equal parts.

Genetic diversity

The variation in genes among individuals in a population.

Centrosomes

Organelles that organize microtubules and are crucial for cell division.

Nuclei

Plural of nucleus; the control center of the cell that contains genetic material.

Kinetochore microtubules

Microtubules that attach to the kinetochores on chromosomes to pull them apart.

Non-kinetochore microtubules

Microtubules that do not attach to chromosomes, helping to elongate the cell.

Decondense

The process by which chromosomes lose their condensed structure and become less visible.

46 chromosomes

The total number of chromosomes in a typical human somatic cell.

22 pairs of chromosomes

The number of autosomes present in human somatic cells.

XX

The sex chromosome configuration for females.

XY

The sex chromosome configuration for males.

Genetically identical

Organisms that have the same genetic makeup.

Cleavage furrow formation

The process where the cell membrane begins to pinch inward to separate daughter cells.

Diversity in population

The variety of different species and genetic differences within a population.

Mutations

Changes in DNA sequence that can lead to variations in offspring.

Centrosomal duplication

The process in which the centrosomes are replicated prior to cell division.

Maternal and paternal chromosomes

Chromosomes inherited from mother and father, respectively.

Sexual reproduction advantages

Increased genetic variation and adaptability among offspring.

Asexual reproduction advantages

Faster reproduction rates and energy efficiency.

Life cycles in organisms

The various reproductive strategies and stages an organism undergoes throughout its existence.

Tetrads in meiosis

Structures formed during meiosis that consist of two homologous chromosomes.

Chiasmata formation

The process essential for genetic recombination between homologous chromosomes.

Cytoplasm division

The process of dividing the cytoplasm during cell division, resulting in separate daughter cells.

Gametes in humans

The sex cells with 23 total chromosomes (22 autosomes and 1 sex chromosome).

Chromatid separation

The process during mitosis or meiosis where sister chromatids are pulled apart.

Fertilization

The union of an egg and sperm resulting in a zygote.

Genetic clones

Organisms that are genetically identical to the parent organism through asexual reproduction.

Energy consumption in reproduction

The amount of energy required for an organism to reproduce, which varies between asexual and sexual reproduction.

Sister chromatid cohesion

The force that holds sister chromatids together at the centromere until anaphase.

Haploid gametes

Cells with half the number of chromosomes (n), produced during meiosis.

Diploid zygote

The fertilized egg resulting from the union of a sperm and egg, containing a full set of chromosomes (2n).

Meiosic division

The process of meiosis which includes two divisions resulting in four non-identical haploid cells.

Reproductive history

The sequence of reproductive events and stages in an organism's life.

Chromosome number reduction

The process during meiosis that reduces the chromosome number from diploid to haploid.

Gene exchange

The process during crossing over which allows for genetic diversity among offspring.

Environmental adaptations through reproduction

Changes in reproductive strategies to better fit an organism to its environment.

Spermatogenesis

The process of sperm cell development in males.

Oogenesis

The process of egg cell development in females.

Gametogenesis

The formation of gametes through cell division and differentiation.

Crossing over significance

Key to genetic variation and diversity among offspring.

Non-sister chromatids

Chromatids from different homologous chromosomes that exchange genetic material.