Bio Chapter 8 Review Flashcards

Flashcards covering key vocabulary terms and concepts from Chapter 8 lecture notes, including DNA structure, cell division, and genetic variation.

Genome

The entire genetic complement (DNA) of an organism

Chromosome

Structures made of chromatin that are visible when the cell is dividing.

Chromatin

DNA wound around proteins forming long fiber like strands

Prokaryotic DNA

Prokaryotic genomes typically consist of a single circular chromosome located in the cytoplasm inside the nucleoid. They also contain plasmids (Small circular DNA molecules separate from the main chromosome)

Eukaryotic DNA: Eukaryotic genomes

Eukaryotic genomes are composed of multiple linear chromosomes found within the nucleus.

DNA Condensation

DNA is first wrapped around proteins called histones, forming structures called nucleosomes. The nucleosomes then coil into chromatin fibers, which are more condensed structures.

Interphase

the period of the cell cycle leading up to mitosis; includes G1, S and G2 phases; the interim between two consecutive cell divisions.

S Phase

making an identical copy of each chromosome.

Prophase

chromosomes condense and become visible

Metaphase

align during metaphase plate in metaphase.

Anaphase

Chromosomes separate and move to opposite poles

Telophase

chromosomes arrive at opposite poles, decondense, and are surrounded by new nuclear envelopes.

Cytokinesis

the division of the cytoplasm following mitosis to form 2 daughter cells

G0 Phase

cell cycle phase distinct from G1 phase of interphase; a cell in G0 isn’t preparing to divide

Cell Cycle

the ordered sequence of events that a cell passes through between one cell division and the next.

Centrosomes

microtubule organizing centers that give rise to mitotic spindle

the equatorial plane midway between two poles of a cell where the chromosomes align during metaphase

Metaphase Plate

Cell Cycle checkpoints

mechanisms that monitor the preparedness of a eukaryotic cell to advance through the various cell cycle stages

Binary Fission

the process of prokaryotic cell division

Septum

a wall formed between bacterial daughter cells as a precursor to cell separation

Asexual reproduction

produces genetically identical clones of the parent organism

Sexual reproduction

requires that two different gametes come together to form a zygote

Gametes

a haploid reproductive sex cell; Sperm or and egg

Haploid

describes a cell, nucleus or organism containing one set of chromosomes

Diploid

describes a cell, nucleus or organism containing two sets of chromosomes

Somatic cells

all the cells of a multicellular organism except the gamete-forming cells

Germline cells

specialized cell line that produces gametes, such as eggs or sperm

Fertilization

the union of two haploid cells typically form individual organisms

Homologous chromosomes

the randomness of how the homologous chromosome pairs align at the metaphase plate during metaphase 1 of meiosis 1

Locus

the position of a gene on a chromosome

Allosomes

chromosomes that play a role in sex determination

Meiosis 1

the first round of meiotic cell division: referred to as reduction division because the resulting cells are haploid

Meiosis 2

the second round of meiotic cell division following meiosis 1; sister chromatids are separated from each other and the result is four unique haploid cells.

Tetrad

two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase 1

Crossing over

the exchange of genetic material between homologous chromosomes that incorporate genes from both parents to the organism forming reproductive cells

Interkinesis

a period of rest that may occur between meiosis 1 and meiosis 2; DNA replication doesn’t take place

Aneuploid

an individual with an error in chromosome number, includes deletions and duplications of chromosome segments

Inversion

the detachment, 180 rotation and reinsertion of a chromosome arm

Euploid

an individual with the appropriate number of chromosomes for their species

Karyogram

the photographic image of a karyotype

Karyotype

the number and appearance of an individual’s chromosomes, including size, binding patterns, and centromere position

Monosomy

an otherwise diploid genotype in which one chromosome is missing

Nondisjunction

the failure of synapse homologs to completely separate and migrate to separate poles during the first cell division in Meiosis

Polyploid

an individual with an incorrect number of chromosome sets

Translocation

the process by which one segment of a chromosome dissociates and reattaches to a different, nonhomologous chromosome

Trisomy

an otherwise diploid genotype in which one entire chromosome is duplicated.

Deletion

a part of a chromosome is lost or removed

Duplication

a part of a chromosome is duplicated and either inserted into a different position on the same chromosome or a completely different chromosome.