Week 4: Cell division and genetic information

Vocabulary flashcards covering cell division, DNA, replication, meiosis, mitosis, checkpoints, and tissue/organ systems.

Cell division

Process by which a parent cell divides to form two or more daughter cells, enabling growth, repair, and reproduction.

Sexual reproduction

Reproduction that requires genetic information from two parents; offspring are genetically different.

Gamete

A haploid reproductive cell (sperm or egg) that fuses with another to form a zygote.

Offspring

The new organism produced by reproduction, genetically related to the parents.

Asexual reproduction

Reproduction involving one parent; offspring are genetically identical to the parent.

DNA

The genetic material that stores the instructions for building a organism’s proteins; normally copied before cell division.

Genes

Sections of DNA that contain instructions to build specific cellular proteins.

Chromosome

A structure made of DNA wrapped around proteins that carries many genes and becomes condensed before cell division.

Sister chromatids

Two identical copies of a chromosome that are held together at the centromere.

Centromere

The region where sister chromatids are attached and where spindle fibers connect during cell division.

Short arm (p)

The shorter arm of a chromosome.

Long arm (q)

The longer arm of a chromosome.

BRCA1 gene

A gene located on chromosome 17q21; an example of a gene involved in DNA repair.

DNA replication

The process by which a cell copies its DNA prior to cell division.

Semiconservative replication

Each new DNA molecule contains one old (parental) strand and one new strand.

DNA polymerase

The enzyme that builds new DNA strands by matching complementary bases.

Double helix

The shape of DNA consisting of two intertwining strands.

Adenine (A)

A DNA base that pairs with thymine (T).

Thymine (T)

A DNA base that pairs with adenine (A).

Cytosine (C)

A DNA base that pairs with guanine (G).

Guanine (G)

A DNA base that pairs with cytosine (C).

Interphase

Phase of the cell cycle when the cell grows and DNA is replicated (includes G1, S, and G2).

S phase

Phase of interphase in which DNA replication occurs.

Mitosis

A type of cell division that produces two genetically identical diploid daughter cells.

Cytokinesis

Division of the cytoplasm that completes cell division.

Prophase

First stage of mitosis; chromosomes condense and the nuclear envelope breaks down.

Metaphase

Stage when chromosomes align at the cell’s equator (metaphase plate).

Anaphase

Stage when sister chromatids separate and move to opposite poles.

Telophase

Stage when new nuclear envelopes form around separated chromosomes.

G1 checkpoint

Checkpoint asking if cell division is necessary and if the cell is large enough to proceed.

G2 checkpoint

Checkpoint checking whether DNA replication was accurate before mitosis.

Metaphase checkpoint

Checkpoint verifying all chromosomes are properly attached to spindle microtubules.

Tumor suppressor

Proteins that monitor cells for abnormalities and can halt cell division to prevent tumors.

Proto-oncogene

Normal gene that promotes cell growth; mutations can convert it into an oncogene.

Oncogene

Mutated proto-oncogene that can drive uncontrolled cell division.

Mutation

A change in DNA sequence that can affect gene function.

Crossing over

Exchange of genetic material between homologous chromosomes during Prophase I of meiosis.

Synapsis

Pairing of homologous chromosomes during meiosis I.

Chiasmata

Points where chromatids exchange genetic material during crossing over.

Haploid

A cell with one set of chromosomes (n).

Diploid

A cell with two sets of chromosomes (2n).

Meiosis

Cell division that produces four genetically unique haploid gametes, increasing genetic diversity.

Meiosis I

First division of meiosis; homologous chromosomes separate, forming two haploid cells.

Meiosis II

Second division of meiosis; sister chromatids separate, producing four haploid gametes.

Random alignment / Independent assortment

Random arrangement of chromosome pairs during meiosis I, increasing gamete diversity.

Organ

A structure made of two or more tissue types working together to perform a function.

Tissue

A group of similar cells that perform a specific function.

Epithelial tissue

Tissue that covers surfaces (e.g., skin) and is used in skin and cornea transplants.

Connective tissue

Tissue such as blood and bone marrow; can be donated by living donors.

Muscle tissue

Tissue that contracts; cardiac muscle can be transplanted within 4 hours of removal.

Nervous tissue

Tissue involved in signaling; rarely used in transplants.

Organ system

A group of organs that perform a common function.

11 major organ systems

The human body contains eleven major organ systems that work together to maintain health.