Life Science Comprehensive Review

Flashcards covering essential life science topics such as genetics, cellular biology, human reproduction, and basic characteristics of living things based on lecture notes.

Genes

Factors that control traits.

Alleles

The different forms of a gene.

Dominant Allele

A trait that always shows up when the allele is present, represented by an uppercase letter.

Recessive Allele

A trait that is hidden when the dominant allele is present, represented by a lowercase letter.

Purebred

An organism with two of the same alleles for a trait, often produced over many generations showing the same trait.

Hybrid

An organism with two different alleles for a trait.

Homozygous

Another term for being purebred for a trait.

Heterozygous

Another term for being hybrid for a trait.

Genotype

The genetic makeup or allele combination of an organism, such as $TT$, $Tt$, or $tt$.

Phenotype

The physical appearance or visible traits of an organism, such as being tall or short.

Probability

A number that describes how likely it is that an event will occur.

Punnett Square

A tool used by geneticists to determine the probability of inheriting specific alleles.

Organism

Any living thing.

Cell

The basic unit of structure and function in living things.

Unicellular

An organism consisting of only one cell.

Multicellular

An organism consisting of many cells.

Stimulus

Any change or signal in the environment that can make an organism react in some way.

Response

An action or a change in behavior resulting from a stimulus.

Instinct

A behavior an organism is born with, such as crying or swallowing.

Learned Behavior

A behavior that an organism must be taught, such as reading or tying shoes.

Life Processes

The things an organism must do to stay alive.

Ingestion

The process of taking in food.

Digestion

The process of breaking down food so that it can be used by living things.

Nutrients

Materials needed for growth and energy.

Cellular Respiration

The process by which a cell releases energy from food molecules; represented as $\text{oxygen} + \text{food (sugar/glucose)} \rightarrow \text{energy} + \text{water} + \text{carbon dioxide}$.

Excretion

The process of getting rid of waste products formed by life processes.

Transport

The process of moving nutrients and wastes throughout a living thing.

Spontaneous Generation

The mistaken idea that living things arise from nonliving sources.

Specialization

Studying or working in only one part of a subject.

Anatomy

The study of the parts of the body.

Physiology

The study of how the whole body functions.

Ecology

The study of the relationship between organisms and their environment.

Zoology

The study of animals.

Botany

The study of plants.

Microbiology

The study of viruses and other microscopic organisms.

Reproduction

The process by which living things produce new organisms like themselves.

Offspring

A new organism produced by a living thing.

Asexual Reproduction

Reproduction requiring only one parent, where the offspring is an exact copy of the parent.

Fission

A type of asexual reproduction where the parent organism splits in two, common in bacteria.

Budding

A type of asexual reproduction involving the growth of a new organism directly from the parent organism.

Sexual Reproduction

Reproduction requiring two parents, where offspring has a mix of features from both.

Homeostasis

The maintenance of stable internal conditions.

Autotroph

An organism that makes its own food, also known as a producer.

Heterotroph

An organism that cannot make its own food and must eat other organisms, also known as a consumer.

Cell Theory

A scientific theory stating that all living things are made of cells, cells are the basic unit of structure and function, and cells are produced from other cells.

Mitochondria

The powerhouse of the cell that produces energy as a result of cellular respiration.

Passive Transport

The movement of materials through a membrane without the cell using energy, such as diffusion and osmosis.

Diffusion

The movement of molecules from an area of high concentration to an area of low concentration.

Osmosis

The diffusion of water through a membrane.

Active Transport

The movement of materials through a membrane using the cell's energy, often involving transport proteins.

Selectively Permeable

A property of membranes that allows some materials to pass through while blocking others.

Nucleus

The control center or brain of the cell, containing genetic material like DNA.

Cytoplasm

The clear, gel-like fluid between the cell membrane and the nucleus where most chemical activities occur.

Endoplasmic Reticulum (ER)

A maze of passageways in the cytoplasm that acts as transportation tubes to carry materials throughout the cell.

Vacuole

Fluid-filled sacs used for storage of water, protein, fat, and wastes.

Ribosomes

Small grain-like bodies that act as protein factories.

Lysosomes

Small round bags containing digesting enzymes that break down food or old cell parts.

Golgi Bodies

Flattened tubes and sacs that package proteins and send them to different parts of the cell.

Cell Wall

A rigid, non-living material made of cellulose that surrounds plant cells for shape and protection.

Chloroplasts

Green sacs found in plant cells where photosynthesis takes place.

Chlorophyll

The green pigment that traps light energy in a chloroplast.

Photosynthesis

The food-making process in plants using sunlight, written as $\text{CO}_2 + \text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + \text{O}_2$.

Stomata

Small openings on the underside of leaves where carbon dioxide enters and oxygen exits.

Ovaries

Female reproductive organs that produce hormones and egg cells.

Oviduct

The tube where fertilization occurs, connecting the ovary to the uterus; also called the Fallopian tube.

Uterus

The muscular organ in which a baby develops.

Vagina

The birth canal and the opening where sperm enters the female reproductive system.

Testes

Male reproductive organs that produce hormones and sperm cells.

Scrotum

The pouch of skin that holds and protects the testes outside the body to maintain a cooler temperature.

Urethra

A tube that carries sperm and urine out of the body in males.

Estrogen

A female hormone that causes secondary sex changes and controls the menstrual cycle.

Testosterone

A male hormone that causes secondary sex changes like a deeper voice and facial hair.

Sperm

The male sex cell, which uses a flagellum to move.

Egg

The female sex cell, also called an ovum.

Ovulation

The process when a mature egg is released from the ovary.

Menstruation

The process where blood and the lining of the uterus leave the body if an egg is not fertilized.

Fertilization

The joining of a sperm cell and an egg cell.

Zygote

A fertilized egg cell; the first cell of a new organism.

Embryo

The developing baby from the zygote stage up to 8 weeks.

Fetus

The developing baby from 8 weeks after fertilization until birth.

Implantation

When the embryo attaches to the wall of the uterus.

Placenta

The organ through which the baby receives food and oxygen and removes waste.

Umbilical Cord

The tube connecting the developing baby to the placenta.

Amnion

The membrane filled with fluid that cushions and protects the developing baby.

Gestation

The period of pregnancy.

Monozygotic Twins

Identical twins formed when one egg is fertilized by one sperm and the zygote splits into two.

Dizygotic Twins

Fraternal twins formed when two separate eggs are fertilized by two different sperm.

Conjoined Twins

Monozygotic twins where the zygote does not completely separate, resulting in babies joined at some part of the body.

Fermentation

An energy-releasing process that does not require oxygen.

Magnification

The amount that a specimen is enlarged, calculated by multiplying the eyepiece lens by the objective lens.