Meiosis and Sexual Life Cycles ch.13

Flashcards related to meiosis, sexual reproduction, and genetic variation.

Meiosis

A nuclear division mechanism that precedes gamete formation in eukaryotic cells, resulting in halving the parental chromosome number.

Gamete

A haploid reproductive cell (sperm or egg) that fuses during fertilization to form a diploid zygote.

Asexual Reproduction

A type of reproduction that involves one parent and produces genetically identical offspring (clones).

Sexual Reproduction

A type of reproduction that involves the fertilization of an egg by sperm, resulting in genetically unique offspring.

Parthenogenesis

A form of asexual reproduction where an egg develops into a new individual without fertilization.

Nondisjunction

An error in meiosis where homologous chromosomes or sister chromatids fail to separate properly, leading to abnormal chromosome numbers in gametes.

Independent Assortment

The process by which alleles of different genes segregate independently during gamete formation.

Crossing Over

The exchange of genetic material between homologous chromosomes during prophase I of meiosis, leading to genetic variation.

Diploid

A cell or organism that has two sets of chromosomes (2n), one from each parent.

Haploid

A cell or organism that has one set of chromosomes (n), typical of gametes.

Zygote

The diploid cell formed when a sperm fertilizes an egg.

Synapsis

The pairing of homologous chromosomes during prophase I of meiosis.

Chiasma

The point where two homologous non-sister chromatids exchange genetic material during crossing over.

Meiosis I

The first division in meiosis that separates homologous chromosomes, resulting in two haploid cells.

Meiosis II

The second division in meiosis that separates sister chromatids, resulting in four haploid daughter cells.

Monosomy

A chromosomal abnormality involving the absence of one chromosome from a pair.

Trisomy

A chromosomal abnormality involving an extra chromosome, resulting in three copies instead of two.

Autosomal Trisomy 21

A genetic condition also known as Down syndrome, which is caused by the presence of an extra chromosome 21.

Life Cycle

The series of changes in the life of an organism, including reproduction.

Sister Chromatids

Identical copies of a duplicated chromosome, connected at the centromere.

Homologous chromosomes

Chromosomes that are similar in shape, size, and genetic content, one inherited from each parent.

Ploidy

The number of sets of chromosomes in a cell.

Dioecious Organisms

Species that have distinct male and female individuals.

Monoecious Organisms

Species that have both male and female reproductive structures on the same individual.

Recombinant Chromosomes

Chromosomes that are formed by combining genetic material from both parents after crossing over.

Genetic Variation

Diversity in gene frequencies, which can arise through mutation, recombination, and independent assortment.

Autosomes

The non-sex chromosomes that are present in both males and females.

Sex Chromosomes

Chromosomes that determine the sex of an individual, X and Y in humans.

Gamete Formation

The process by which cells undergo meiosis to produce sex cells (gametes).

Diploid Multicellular Organism

An organism composed of cells that have two sets of chromosomes.

Haploid Gametophyte

A multicellular stage in the life cycle of plants that is haploid and produces gametes.

Diploid Sporophyte

A multicellular stage in the life cycle of plants that is diploid and produces spores.

Binary Fission

A form of asexual reproduction in prokaryotes where a cell divides into two identical cells.

Fragmentation

A form of asexual reproduction where an organism breaks into fragments, each capable of growing into a new individual.

Vegetative Propagation

A form of asexual reproduction in plants where new plants grow from parts of the parent plant.

Sister Chromatid Cohesion

The process that holds sister chromatids together until anaphase in both mitosis and meiosis.

Chiasmata Formation

The formation of connections between homologous chromosomes during synapsis in prophase I.

Fertilization

The process of fusing male and female gametes to form a zygote.

Spindle Apparatus

Structure that separates chromosomes during cell division, composed of microtubules.

Cleavage Furrow

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

Cytokinesis

The process of cytoplasmic division that occurs at the end of cell division.

Prophase I

The first phase of meiosis I where homologous chromosomes pair and crossing over occurs.

Anaphase I

The phase of meiosis I where homologous chromosomes are pulled apart to opposite poles.

Anaphase II

The phase of meiosis II where sister chromatids are separated and moved to opposite poles.

Telophase II

The final phase of meiosis II where four haploid daughter cells are formed.

Reducing Chromosome Number

The primary function of meiosis, reducing the chromosome number in gametes.

Random Fertilization

The concept that any sperm can fertilize any egg, increasing genetic diversity.

Polyploidy

Condition in which an organism has more than two complete sets of chromosomes.

Meiotic Errors

Mistakes that occur during meiosis, which may result in chromosomal abnormalities.

Aneuploidy

An abnormal number of chromosomes in a cell, often arising from nondisjunction.

Genetic Disorders

Medical conditions caused by abnormalities in the genome, which can arise from meiotic errors.

Evolutionary Adaptation

Change in organisms that enhances their survival and reproduction in their environment.

Courtship Displays

Behavioral displays that are part of the mating process in many sexually reproducing species.

Nesting Behavior

Actions taken by animals to build nests for laying eggs or rearing young.

Parental Care

Behavior exhibited by animals to care for and protect their offspring after birth.

Chromosome Duplication

The process of copying DNA prior to cell division, ensuring each daughter cell gets a complete set.

Nuclear Envelope

The double membrane that encloses the nucleus in eukaryotic cells.

Gamete Fusion

The process where two gametes combine to form a zygote during fertilization.

Somatic Cells

Any cells in the body except for sperm and egg cells.

Haploid Life Cycle

A life cycle where the haploid stage is dominant and multicellular.

Diploid Life Cycle

A life cycle characterized by a dominant diploid stage.

Zygotic Life Cycle

A life cycle where the unicellular zygote is the only diploid stage.

Phenotype

The observable physical or biochemical characteristics of an organism.

Genotype

The genetic constitution of an organism, which determines its traits.

Allele

Different forms of a gene that can exist at a specific locus.

Hybridization

The process of breeding individuals from different varieties or species.

Environmental Influence

Effects of environmental factors on the expression of genes and traits.

Adaptive Radiation

The diversification of a group of organisms into forms filling different ecological niches.

Mendelian Inheritance

Patterns of inheritance proposed by Gregor Mendel, including concepts of dominance, segregation, and independent assortment.

Genetic Drift

Random changes in allele frequencies in a population due to chance events.

Natural Selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Speciation

The evolutionary process by which populations evolve to become distinct species.

Biotechnology

The use of biological systems or living organisms to develop or create products.

Cloning

The process of producing genetically identical individuals from a single organism.

Genome

The complete set of genes or genetic material present in a cell or organism.

Gene Therapy

A technique that modifies a person's genes to treat or prevent disease.

CRISPR

A revolutionary technology that allows for precise editing of DNA.

Bioinformatics

The use of computer technology to manage and analyze biological data.

Molecular Biology

The branch of biology that deals with the molecular basis of biological activity.

Eukaryotic Cells

Cells that have a nucleus enclosed within membranes, unlike prokaryotic cells.

Chromatin

The complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells.

Genetic Code

The set of rules that determines how the sequence of nucleotides in DNA translates into amino acids.

Ribosomes

Molecular machines in cells that synthesize proteins based on genetic instructions.

Transcription

The process of copying a segment of DNA into RNA.

Translation

The process by which ribosomes synthesize proteins using the information in mRNA.

Codon

A sequence of three nucleotides that corresponds to a specific amino acid.

Anticodon

A sequence of three nucleotides in tRNA that complements a codon in mRNA.

Modifications during RNA processing

Chemical changes to RNA after transcription that are necessary for translation.

Mutation

A change in the DNA sequence that may lead to different traits.

Recessive Allele

An allele that is masked by the presence of a dominant allele.

Dominant Allele

An allele that expresses its phenotypic effect even in a heterozygous condition.

Homozygous

Having two identical alleles for a particular gene.

Heterozygous

Having two different alleles for a particular gene.

Fertilization Process

The combination of male and female gametes during reproduction.

Life History Strategy

The overall pattern in the growth, reproduction, and survival of an organism.

Laboratory Techniques

Methods used in science to conduct experiments and analyze data.

Molecular Cloning

The process of making copies of specific DNA fragments for analysis.

Gene Expression

The process by which information from a gene is used to synthesize functional gene products.

Reverse Genetics

A method for understanding the function of a gene by analyzing phenotypic effects of specific engineered gene sequences.

Embryonic Stem Cells

Undifferentiated cells that can develop into any cell type of the body.