AP Bio Unit 2 - Cell Structure and Function Diagram

Cell

The smallest unit of living matter

Cell theory

1. All organisms are composed of cells

2. Cells are the basic unit of structure and function in organisms

3. Cells only come from preexisting cells

Surface area to volume ration (SA:V)

Calculation relating cell surface area to size; this is important for cells because they need to be able to exchange material efficiently into and out of the cell; large SA:V ratio is favorable to cells

Prokaryotic cells

Bacteria; single-celled organisms; do not contain a nucleus or other membrane-bound organelles

Eukaryotic cells

examples include plant, animal, fungi, and protist cells; more complex and contain a nucleus and membrane-bound organelles

Endosymbiosis theory

Mitochondria and chloroplasts were once bacteria cells that were engulfed by larger cells, but instead of being broken down, a symbiotic relationship was created where the smaller cells provide energy and the bigger cell provides protection; evidence for this is that both contain their own DNA and ribosomes, and they are able to reproduce independently of the cell

Nucleus

Contains DNA and controls activities of the cell

Nucleolus

Located within the nucleus, synthesizes subunits of ribosomes

DNA

Genetic material located in ALL cell types; thread-like chromosomes in eukaryotic cells are located in the nucleus; circular DNA of prokaryotic cells is located in the cytoplasm

Ribosome

Manufactured in the nucleolus; consists of rRNA and protein; assists in making proteins; found attached to the rough ER or floating in the cytoplasm

Rough Endoplasmic Reticulum

Stacks of flattened sacs with ribosomes on the surface involved in the production of proteins

Smooth Endoplasmic Reticulum

Stacks of flattened sacs without ribosomes; responsible for various activities, including the synthesis of lipids and hormones

Golgi Apparatus

Modify and package proteins and lipids into vesicles

Vesicles

Small, spherically shaped sacs that bud from the outside surface of the Golgi apparatus; often migrate to and merge with the plasma membrane, releasing their contens to the outside of the cell

Lysosomes

Vesicles from a Golgi apparatus that contain digestive enzymes; break down food, cellular debris, and foreign invaders such as bacteria

Peroxisomes

Break down various substances, fatty acids, and amino acids; combine hydrogen from these substances with oxygen to form hydrogen peroxide; common in liver and kidney cells

Mitochondria

Carry out aerobic respiration, where carbohydrates are broken down to to create energy in the form of ATP.

Chloroplasts

Carry out photosynthesis in plant cells using energy from sunlight

Flagella

Structures that protrude from the cell membrane; long, few (usually single), move in a whiplike motion Ex: propels sperm

Cilia

Structures that protrude from the cell membrane; short, many, move with a back and forth movement Ex: line the resp. tract and sweep away debris

Centrosomes

Microtubule organizing centers. A centriole pair is located outside the nuclear envelope, which gives rise to the microtubules that make up the spindle apparatus used to move chromosomes during cell division. Also builds cytoskeletal structures to move organelles and proteins.

Centriole

Short cylinders with nine triplets of microtubules; two centrioles create a centrosome and are involved in cytoskeleton management

Cytoskeleton

Internal support system for the cell that also anchors and organizes organelles; composed of microtubules, microfilaments, and intermediate filaments

Central vacuole

Large sac occupying most of the interior of certain plant cells; store nutrients, water, and waste, and carry out functions otherwise assumed by lysosomes in animal cells

Contractile vacuoles

Specialized organelles in prokaryotic organisms that collect and pump excess water out of the cell

Cell wall

Found in plants and bacteria; develop outside the plasma membrane and provide support for the cell; in plants, it consists mainly of cellulose

Cell membrane (plasma membrane)

A phospholipid bilayer that contains other proteins, lipids, and carbohydrates to control movement into and out of the cell and communicate with other cells

Fluid Mosaic Model

Describes the cell membrane; fluid do to the phospholipids and cholesterol that allow the membrane to change shape in various temperatures without becoming to rigid or falling apart; mosaic because the proteins move and change based on the cell and changes in the environment.

Selectively permeable

Describes the cell membrane because it allows only certain substances into the cell while keeping others out of the cell.

Channel proteins

Open proteins that allow certain molecules to enter/ exit the cell.

Carrier proteins

Proteins that change shape and control the movement of specific molecules to cross the cell membrane.

Cell recognition proteins

Glycoproteins (proteins with carbohydrate chains) that identify specifics about the cell.

Receptor proteins

Proteins with a specific shape where molecules attache to the protein on the outside of the cell membrane to create a signal inside the cell for communication.

Enzymatic proteins

Proteins that cause reactions with specific molecules

Junction proteins

Create junctions between different cells.

Extracellular matrix

Found in animals in the area between adjacent cells; occupied by fibrous, structural proteins like collagen; provides mechanical support and helps bind adjacent cells together

Tight junctions

Tightly stitched seams between animal cells; completely encircles each cell, producing a seal that prevents the passage of materials between cells

Gap junctions

Narrow tunnels between animal cells; prevents the cytoplasm of each cell from mixing but allows the passage of ions and small molecules; allows communication between cells through the exchange of materials

Aquaporins

Channel proteins that specifically allow water to readily cross the cell membrane.

Concentration gradient

Describes the number of molecules between two areas. Molecules want to move from high concentration to low concentration to reach equilibrium.

Passive transport

Molecules moving through the plasma membrane or a channel protein from high to low concentration.

Facilitated transport

Molecules move through a carrier protein from high to low concentration.

Active transport

Molecules moving through a carrier protein from low to high concentration; requires energy

Plasmodesmata

Narrow channels between plant cells; resemble the gaterm-26p junctions of animal cells

Exocytosis

Moving materials out of the cell

Endocytosis

Moving materials into the cell

Phagocytosis

"Cell eating"; undissolved material enters the cell; Plasma membrane wraps around the solid material and engulfs it; ex: white blood cells

Pinocytosis

"Cell drinking"; dissolved or liquid material enters the cell by being engulfed into a vesicle.

Receptor-mediated endocytosis

A form of pinocytosis where receptor proteins recognize specific molecules when attached and then engulf the molecules into a vesicle.

Diffusion

The movement of molecules from a higher to a lower concentration

Osmosis

The diffusion of water across a selectively permeable membrane from high to low concentration.

Osmotic pressure

The pressure that develops in a system due to osmosis

Isotonic solution

When the solute concentration and water concentration are equal both inside and outside the cell

Hypertonic solution

When a solution outside of a cell has more solute, and thus is at a higher concentration; leads to water leaving the cell; can cause cells to lose too much water and die

Hypotonic solution

When a solution outside of a cell has less solute, and thus is at a lower concentration; leads to water entering the cell; can cause animal cells to burst

Turgor pressure

Osmotic pressure that develops when water enters the cells of plants and increases the size of the central vacuole; gives the leaves a firm appearance

Golge Apparatus

Smooth ER