ABRHS AP Biology Unit 2: Cell Structure and Function

Cell (Plasma) Membrane

Cell (Plasma) Membrane

Phospholipid bilayer that regulates cell transport; involved in cell to cell recognition.

Cell Wall

The outermost layer in plant cells and prokaryotes. Composed of chitin in fungi, cellulose in plants, peptidoglycans in prokaryotes.

Plasmodesma

Small pores in the cell wall which appear to allow a bridge of cytoplasm from one cell to the next.

Vacuole

Site of storage of glucose, water, salts, and toxic substances. Larger in plant cells that animal cells.

Smooth Endoplasmic Reticulum

It forms a link between the nuclear membrane and the cell. Site of carbohydrate and lipid synthesis. It also helps breakdown toxic substances

Chloroplast

Site of photosynthesis in the plant and algal cell.

Thylakoid

A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy.

Granum (Grana)

A stack of thylakoids in a chloroplast

Cytoplasm

Jelly-like material surrounding the nucleus of the cell; chemical reactions take place here.

Chromoplast

Plastids that produce and store pigment s for color.

Golgi Apparatus

A delivery system of folded membranes that sort and transport enzymes and hormones made in one part of the cell and needed in another location in the cell.

Ribosomes

Site of protein synthesis, made up of rRNA.

Rough Endoplasmic Reticulum

Forms a link between the nuclear membrane and the cell. Ribosomes are attached to the surface. Proteins are synthesized in the ribosomes and enclosed in vessicles and sent to the Golgi.

Mitochondria

The site of cellular respiration or energy production. Membrane bound.

Microtubule

Serves as a structural components within cells and are involved in many cellular processes including mitosis and cytokinesis.

Microfilament

These form in the cytoskeleton, a three dimensional net work inside a eukaryotic cell.

Lysosome

Contains enzymes needed for digesting food, viruses, bacteria, and old cells.

Centrioles

Not normally found in plant cells. They are found in animal cells in pairs and are necessary for cell division.

Nuclear Membrane

Porous; surrounds the nucleus.

Nuclear pores

Small holes in the membrane of the nucleus where RNA can pass through.

Nucleolus

Site of ribosomes synthesis.

Chromatin

Hereditary material in the cell.

Nucleus

The control center of the cell; directs the making of proteins and cell division.

Cytoskeleton

Network of microtubules and microfilaments used for support and movement of the cell.

Plastid

Responsible in photosynthesis, storage of products like starch and for the synthesis of many classes of molecules such as fatty acids.

Cytosol

Part of the cytoplasm that is not held by any of the organelles in the cell.

Centrosome

Small region of cytoplasm adjacent to the nucleus that contains the centrioles and serves to organize microtubules.

Peroxisomes

Small, membrane-enclosed organelles that contain the enzyme involved in a variety of metabolic reactions such as catalase.

Contractile Vacuole

A membrane-bound organelle found in certain protists that function in osmoregulation.

Endomembrane system

A system involved in moving resources/materials in and out of the cell. It uses both the Smooth and Rough Endoplasmic Reticulum, the Golgi Apparatus, lysosomes, vacuoles, and vesicles formed by the plasma membrane

Water Potential

the physical property that predicts the direction in which water will flow.

Tonicity

the ability of a solution to cause a cell to gain or lose water

Isotonic

when the concentration of two solutions is the same

Hypertonic

Having a higher concentration of solute than another solution.

Hypotonic

Having a lower concentration of solute than another solution

Turgor Pressure

The pressure that water molecules exert against the cell wall

Glycoproteins

Membrane carbohydrates that are covalently bonded to proteins. They help with cell-cell recognition and the formation of adhesion junctions between cells.

Glycolipids

Membrane carbohydrates that are covalently bonded to lipids. They also play a role in cell-cell recognition and help stabilize the cell membrane.

Cholesterol

A lipid that forms an essential component of animal cell membranes. It is used to maintain the fluidity of the cell membrane.

Plasmolysis

Collapse of a walled cell's cytoplasm due to a lack of water

Crenation

in animal cells, shriveling of the cell due to water leaving the cell when the environment is hypertonic.

Carrier proteins

Proteins that bind solutes and transport them across the plasma membrane

Transport proteins

A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.

Active transport

Energy-requiring process that moves material across a cell membrane against the concentration gradient.

Passive transport

the movement of substances across a cell membrane without the use of energy by the cell.

simple diffusion

Movement of a solute from an area of high concentration to an area of low concentration

Facilitated diffusion

the movement of molecules through a channel protein that is activated by a ligand. Molecules will be unable to cross unless the protein is opened. It is passive transport

Gated channel

A transmembrane protein channel that opens or closes in response to a particular stimulus.

Sodium-Potassium pump

A special transport protein in the plasma membrane of animal cells that transports sodium out of the cell and potassium into the cell against their concentration gradients. Especially important in nerve cells for the sending of signals.