Module 4 - Science

Cell Structure and Function

Cytology 

The study of cells

Ingestion

The ability to take in nutrients; this includes absorption, which is the ability to bring dissolved materials into the cell

Digestion

The ability to break food or nutrients down into simpler forms (by hydrolysis or with the help of enzymes) so it can be utilized

Respiration

The ability to release energy from the breakdown of food molecules

Transport

The ability to distribute or circulate molecules from one part of the cell to another

Homeostasis

The ability to maintain internal stability (also known as regulation)

Synthesis

The ability to combine simple compounds into complex molecules (same as biosynthesis)

Secretion

The ability to release biosynthesized substances

Excretion

The ability to remove soluble metabolic waste from the cell

Egestion

The ability to remove non-soluble, undigested waste from the cell

Irritability

The ability to respond to stimuli

Movement

The ability to move

Reproduction

The ability to produce more cells

Organelle

A tiny structure that carries out a specific function necessary for the cell to survive

Prokaryotic cell

A cell that has no nucleus or other distinct, membrane-bound organelles

Eukaryotic cell

A cell with a membrane-bound nucleus and other distinct, membrane-bound organelles

Plasma membrane

The semipermeable membrane between the cell contents and the cell’s surroundings

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Cytoplasmic streaming

The motion of cytoplasm in a cell that results in a coordinated movement of the cell’s content

Ribosomes

Non-membrane-bound organelles responsible for protein synthesis

Cell Wall

A rigid structure on the outside of certain cells, usually plant and bacteria cells

Middle lamella

The thin film between the cell walls of adjacent plant cells

Nuclear Membrane

A highly porous membrane that separates the nucleus from the cytoplasm

Chromatin

Long strands of clusters of DNA and proteins (or RNA and proteins) in the nucleus of a cell

Endoplasmic reticulum

An organelle composed of an extensive network of folded membranes that performs several tasks within a cell

Rough ER

ER that is dotted with ribosomes

Smooth ER

ER that has no ribosomes

Golgi apparatus

The organelles where proteins and lipids are stored and then modified to suit the needs of the cell

Vacuole

Larger membrane-bound organelle used for storage of food, water, or waste

Vesicle

Smaller membrane-bound organelle used mainly for transport of food, waste, or products synthesized for secretion

Secretory vesicle

Vesicle that holds products of biosynthesis (like proteins) and transports them to the plasma membrane for secretion

Central Vesicle

A large vacuole that rests at the center of most plant cells and is filled with water

Lysosome

The organelle in animal cells responsible for hydrolysis reactions that break down proteins, carbohydrates (polysaccharides, disaccharides), and some lipids

Peroxisome

A cell organelle containing enzymes that catalyze the decomposition of fatty acids and hydrogen peroxide

Mitochondria

Double-membrane-bound organelles in which nutrients are converted to energy

Plastids

Double-membrane-bound organelles found in the cells of plants, algae, and some protozoa, generally involved in either the manufacture or storage of food

Chloroplasts

Plastids containing the green pigment, chlorophyll, used in photosynthesis

Chromoplasts

Plastids containing yellow, orange, or red pigments used in photosynthesis

Leucoplasts

Nonpigmented plastids that store starched or oils

Cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

Microfilaments

Fine, threadlike proteins found in the cell’s cytoskeleton

Intermediate filements

Threadlike proteins in the cell’s cytoskeleton that are roughly twice as thick as microfilaments

Microtubules

Spiral strands of protein molecules that form a tubelike structure

Centrioles

Paired organelles (positioned at right angles to each other) that organize fibers required for cell division; found in animal cells

Centrosome

A small region near the nucleus that is the main organizing site for microtubules; in animal cells it contains the two centrioles