Science Unit 1 Review: Cell Division, Reproduction, Genetics, and Human Development

Comprehensive vocabulary flashcards covering the cell cycle, mitosis, meiosis, cancer, asexual and sexual reproduction, genetics, inheritance, and the male and female reproductive systems.

Cell Division

A biological process necessary for growth to adult, repairing cuts and bones, and replacing damaged cells.

Interphase

The stage of the cell cycle where the cell performs its normal functions, replicates DNA, grows, and prepares for cell division.

Mitosis

The stage of the cell cycle where the nucleus divides through PMAT, producing two genetically identical daughter cells with full DNA (diploid cells).

Cytokinesis

The stage of the cell cycle where the rest of the cell contents divide.

Prophase

The first stage of mitosis in which chromosomes condense and shorten, the nuclear membrane begins to dissolve, and mitotic spindles form.

Metaphase

The stage of mitosis where chromosomes line up in the middle of the cell and the membrane fully breaks down.

Anaphase

The stage of mitosis where chromosome strands separate and move to opposite ends of the cell, ensuring both sets of chromosomes are identical and have the same genetic information.

Telophase

The mitotic stage where chromosomes reach opposite sides of the cell, spindles disappear, a new nuclear membrane forms around each set, and chromosomes lengthen and become less condensed.

Haploid

Cells that contain only one set of chromosomes.

Diploid

Cells that contain two sets of chromosomes.

Cancer

A disease where uncontrolled cell division creates a clump of cells known as a tumor.

Benign Tumor

A clump of cells that physically crowds surrounding cells and organs but does not spread throughout the body; considered non-cancerous.

Malignant Tumor

A clump of cells that can invade and damage surrounding cells and organs, or spread to a different part of the body; considered cancerous.

Asexual Reproduction

Reproduction that involves only one parent, producing identical offspring quickly but offering no genetic variation.

Budding

A type of asexual reproduction where a parent produces a small bud or miniature clone that either detaches (e.g., yeast) or stays attached to form a larger structure (e.g., coral).

Fragmentation

A type of asexual reproduction where new individuals are formed from an existing piece of the parent (e.g., starfish, species of worms, planarian).

Grafting

The process of joining one plant with another plant while allowing both plants to maintain their own DNA and genetic identity (e.g., roses, grapes, citrus trees).

Sexual Reproduction

Reproduction that occurs when two parents supply genetic information to offspring, creating genetic variation.

Internal Fertilization

A form of fertilization in animals where the egg cell is protected inside the female body (e.g., birds, mammals, insects, reptiles).

External Fertilization

A form of fertilization in animals that usually occurs in water so eggs and sperm do not dry out (e.g., many fish, amphibians, worms, sponges).

Meiosis

A cell division process occurring in sex cells with two divisions to produce four genetically unique daughter cells containing half the DNA (haploid cells) that do not divide again.

Characteristic

A general feature of an organism, such as eye color or wing shape.

Trait

A variation of a characteristic, such as brown eyes versus blue eyes.

Heredity

The transmission of characteristics from one generation to the next.

Heritable Characteristics

Characteristics that can be passed from parent to offspring, such as eye color, hair color, height, hair texture, and skin color.

Non-heritable Characteristics

Characteristics that cannot be passed down to offspring, such as piercings, tattoos, scars, dyed hair, straight teeth from braces, injuries, and changes from surgeries.

Chromosomes

Bundles of DNA found in the nucleus.

DNA (Deoxyribonucleic Acid)

A long molecule that stores a cell's genetic information, which directs the cell's functions.

Dominant

The gene that shows up in a trait.

Recessive

The 'hidden' gene in a trait.

Punnett Square

A diagram used to show possible gene combinations.

Homozygous (Pure)

A genetic state where both alleles for a trait are the same.

Heterozygous (Hybrid)

A genetic state where the alleles for a trait are not the same.

Allele

A possible version of a gene that codes for a specific trait, with one received from each biological parent.

Phenotype

The physical traits of a person.

Genotype

The genetic traits of a person.

Gametes

Reproductive cells produced through meiosis.

Sex Chromosomes

Chromosomes that determine the sex of most organisms ($X$ and $Y$; male is $XY$, female is $XX$).

Testis

A male reproductive gland made up of seminiferous tubules and the epididymis.

Epididymis

A structure on top of the testis that stores sperm.

Penis

The male organ that delivers sperm during reproduction.

Scrotum

A sac that protects the testes and helps keep them cool.

Urethra (Male)

A tube leading to the outside of the body that expels urine and semen.

Vas Deferens

Tubes where sperm travels from the epididymis to the urethra.

Seminiferous Tubules

Tiny tubes inside the testis that produce sperm.

Prostate Gland

A gland that helps produce seminal fluid that combines with sperm to make semen.

Vagina

A muscular tube that acts as the birth canal.

Ovary

A female reproductive gland that stores and releases egg cells held at the second division of meiosis.

Uterus

A hollow, muscular organ where the fetus develops.

Fallopian Tube (Oviduct)

A tube that guides an egg from the ovary to the uterus.

Cervix

The structure that connects the vagina to the uterus.

Follicle

A fluid-filled sac in the ovary that stores egg cells held at the second division of meiosis.

Menstrual Cycle

A natural monthly series of hormonal and physical changes in the body that prepares the reproductive system for potential pregnancy.

Fertilization

The union of a sperm cell with an egg cell to form a single-celled zygote.

Implantation

The process where the embryo reaches the uterus and attaches itself onto the endometrium that lines the uterus.

Fetus

The developing embryo once it has been implanted for 8 or 9 weeks.

Birth

The process occurring once the fetus has developed for nine months, when it is ready to leave the mother's uterus.