SA PT 2 Cell Structures and Functions

Organelle

A specialized structure within a cell that performs a specific function.

Nucleus

The organelle that contains the cell’s DNA and controls the cell’s activities.

Cytoplasm

The fluid-filled region between the nucleus and the plasma membrane.

Plasma membrane

The membrane surrounding the cell.

Phospholipid

The molecule that forms the basic structure of the plasma membrane.

Polar end

The water-attracting end of a phospholipid.

Nonpolar end

The water-repelling end of a phospholipid.

Cholesterol

The substance that stabilizes the plasma membrane.

Protein

The type of molecule that helps transport substances or acts as receptors.

Ribosome

The site of protein synthesis.

Smooth ER

The organelle that synthesizes lipids and detoxifies chemicals.

Golgi apparatus

The organelle that packages and modifies proteins.

Secretory vesicle

The vesicle that transports proteins to the membrane for export.

Lysosome

The organelle that contains digestive enzymes.

Mitochondria

The organelle that produces energy (ATP) for the cell.

Cytoskeleton

The structure that gives shape and support to the cell.

Microtubules

Hollow tubes involved in cell movement and structure.

Microfilaments

Thin filaments involved in movement and structure.

Intermediate filaments

Ropelike fibers providing mechanical support.

Cilia

Short hair-like structures used for movement.

Flagellum

A long whip-like tail used for movement.

Microvilli

Small projections that increase surface area.

Diffusion

The movement of molecules from high to low concentration.

Osmosis

The diffusion of water through a semipermeable membrane.

Osmotic pressure

The pressure required to stop osmosis.

Hypertonic

Describes a solution with higher solute concentration.

Lysis

The bursting of a cell in a hypotonic solution.

Facilitated diffusion

The passive movement of molecules via carrier proteins.

Active transport

Using ATP to move substances against a concentration gradient.

Endocytosis

The process of a cell engulfing substances.

Exocytosis

The release of substances from a cell.

Transcription

The process of copying DNA into mRNA.

mRNA

The molecule that carries the genetic message to the ribosome.

tRNA

Brings amino acids to the ribosome.

Translation

The process of assembling proteins from amino acids.

Diploid

Describes cells with a full set of chromosomes.

Autosomes

Non-sex chromosomes.

Interphase

The cell’s phase of growth and DNA replication.

Prophase

The mitotic phase involving chromosome condensation and spindle formation.

Metaphase

The mitotic phase where chromosomes line at the cell equator.

Anaphase

The phase in which sister chromatids are pulled apart.

Telophase

The phase where the nucleus reforms around chromatids.

Chromatids

Identical halves of a duplicated chromosome.

Centromere

The structure that joins sister chromatids together.

Gametes

The reproductive cells (sperm and egg).

Haploid

Describes cells with half the number of chromosomes.

Tetrad

The paired set of homologous chromosomes during meiosis.

Interkinesis

The rest phase between meiosis I and II.

Differentiation

The process of cells becoming specialized.

Anatomy

The study of body structure.

Physiology

The study of body functions.

Homeostasis

The mechanism that maintains a stable internal environment.

Facilitated diffusion or active transport

The mechanism that transports water-soluble substances through a membrane.

Cytoskeleton filaments

The threadlike structures that help maintain cell shape.

Cilia or flagella

The hair-like projections on the cell surface.

Mitochondria

The organelle responsible for producing energy.

Lysosome

The organelle that digests cellular debris.

The circulatory system

The system responsible for transporting oxygen and nutrients.