Bio-sci

Cells

The smallest living unit in all organisms, made up of genetic information and capable of division.

Prokaryotes

Unicellular organisms such as bacteria and archaea that have genetic material but no nucleus or membrane-bound organelles.

Eukaryotes

Complex cells found in plants, animals, fungi, and protists that have genetic material in a nucleus and membrane-bound organelles.

Membrane bound organelles

Specialized organelles found in eukaryotic cells, such as the nucleus, mitochondria, and Golgi apparatus.

Cell membrane/plasma membrane

The selectively permeable barrier that separates the inside of the cell from its environment and controls the movement of materials.

Homeostasis

The self-regulating process by which a living organism maintains internal stability while adjusting to changing external conditions.

Organelles

Specialized parts of a cell that have unique jobs to perform.

Nucleus

The control center of the cell that contains DNA or genetic material and dictates the cell's activities.

Chromatin

The spread-out form of DNA found inside the nucleus, which condenses into chromosomes during cell division.

Ribosomes

Small organelles that synthesize proteins and are produced in the nucleolus.

Endoplasmic reticulum (ER)

A membrane-enclosed passageway for transporting materials, with rough ER having ribosomes attached and smooth ER lacking ribosomes.

Golgi apparatus/Golgi body

An organelle that receives proteins from the ER, modifies them, and prepares them for transport.

Vacuoles

Sack-like structures that store different materials, with the central vacuole storing water in plant cells and lysosomes acting as garbage collectors in animal cells.

Mitochondria

The powerhouse of the cell that generates energy through cellular respiration and contains its own DNA.

Cytoskeleton

A collection of fibers that provide support for the cell and its organelles.

Chloroplast

An organelle found in plant cells where photosynthesis occurs, containing chlorophyll and capturing sunlight for energy.

Cell wall

A rigid structure outside the cell membrane in plant cells that provides shape, support, and protection.

Cilia

Microscopic, hair-like projections found in cells lining the respiratory tract in humans, helping to trap inhaled particles.

Flagella

Tail-like structures that help cells move or propel themselves, found in some bacteria and the sperm cell in humans.

Endocytosis

The process by which cells engulf particles or substances from the external environment.

Fluid mosaic model

The description of the cell membrane's structure as a flexible boundary made up of a lipid bilayer, proteins, and carbohydrates.

Lipid bilayer

The double layer of phospholipids in the cell membrane, with hydrophilic heads attracted to water and hydrophobic tails repelling water.

Semi-permeable

Allowing only certain select materials to pass through the cell membrane.

Cell cycle

The series of events that a cell goes through as it grows and divides into two new cells.

Somatic cell

Any cell in the body of an organism, except for sex cells such as sperm and egg cells.

Cell cycle

The sequence of cell growth and division.

Interphase

The state in which a cell spends most of its life, consisting of three phases - G1, S, and G2.

G1 phase

The phase of interphase where a cell grows and carries out its function.

S phase

The phase of interphase where DNA replication occurs.

G2 phase

The phase of interphase where further preparations for cell division take place.

M phase

The phase of the cell cycle where cell division occurs, consisting of mitosis and cytokinesis.

Mitosis

The division of the cell's nucleus during the M phase.

Cytokinesis

The division of the cytoplasm during the M phase.

Prophase

The first phase of mitosis, where chromatin condenses into chromosomes and spindle fibers form.

Metaphase

The second phase of mitosis, where chromosomes align along the equator of the cell.

Anaphase

The third phase of mitosis, where sister chromatids separate and move towards opposite poles of the cell.

Telophase

The final phase of mitosis, where a nuclear membrane re-forms and chromosomes disperse into chromatin.

Meiosis

The type of cell division that produces gametes.

Meiosis I

The first stage of meiosis, consisting of prophase I, metaphase I, anaphase I, and telophase I.

Meiosis II

The second stage of meiosis, consisting of prophase II, metaphase II, anaphase II, and telophase II.

Diploid

The original cell in both mitosis and meiosis, containing two sets of chromosomes.

Haploid

The daughter cells resulting from meiosis, containing only one set of chromosomes.

Gametes

Sex cells such as sperm and egg cells.

Genetic variation

The result of crossing over and independent assortment during meiosis, leading to genetically different gametes.