AP Biology Chapter 4: Cell Structure and Function

Cell

The smallest unit that can retain the properties of life.

Cell Theory

•all cells are basic unit of life

•all cells are from existing cells

•basic unit of structure and function

Surface-to-Volume Ratio

An object volume increases with the cube of its diameter, but the surface area increases only with the Square. Want to sell expands in diameter growth, it's volume increases faster than the surface area.

Plasma Membrane

•the outer most membrane containing phospholipids

Nucleus

contains DNA and is the largest organelle

Cytoplasm

•everything between the plasma membrane and region of DNA

Prokaryotic Cell

A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea.

Eukaryotic Cells

Contain a nucleus and other organelles that are bound by membranes.

Organelle

specialized structure that performs important cellular functions within a eukaryotic cell

Nucleolus

Makes ribosomes

Nuclear Envelope

Double membrane perforated with pores that control the flow of materials in and out of the nucleus.

Rough ER

A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm; covered with ribosomes that make membrane proteins and secretory proteins.

Golgi bodies

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

Vesicle

Small membrane-bound organelle in the cytoplasm that transport, store and digest substances.

Lysosome

cell organelle filled with enzymes needed to break down certain materials in the cell

Peroxisomes

organelle that contains enzymes convert H2O2 into H2O and oxygen

Mitochondria

An organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.

plasmids

small circular DNA molecules that replicate separately from the bacterial chromosome

Chloroplasts

converts sun light energy into chemical energy of ATP which is used to make sugar and organic compounds.contains stroma, thylakoid, granum, pigments

Stroma

Fluid inside the chloroplasts

Thylakoid

Disk-shaped compartments in chloroplasts

Granum

Stack of thylakoid

Central Vacuole

•in plant cells

•stores amino acids, sugars, ions, toxic wastes

•as it enlarges causes cell to enlarge

•50-90% of cell interior

Microtubules

A hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella.

Tublin

A protein made of two polypeptide chains folded into a globular shape

Actin filaments

protein fibers that play a role in movement of cell and organelles and also the shape of a cell

Intermediate Filaments

most stable element of cytoskeleton, strengthen cells and helps maintain shape, animal cells only

Centriole

Cell structure, existing in pairs, that occurs in the centrosome and may help organize a mitotic spindle for chromosome movement during animal cell division.

Cell Wall

•surrounds plasma membrane

•protects and supports cells

•porous so water and solutes can move through

•plants, bacteria, fungi

•woody plants 25% of secondary wall is lignin

Lignin

Stronger, waterproof, less inviting to insects.

Junctions

Where the cell sends and receives signals and materials, where it recognizes and cements itself the cells of the same type

Plasmodesma

Channel of walls of plants

Tight junctions

•link cells of epithelial tissue

•deals adjoining cells together, water tight

Adhering Junctions

Joins cells in tissues of skin, heart and other organs subject to stretching

Gap junctions

Link cytoplasm to neighboring cells open up channels

glycocalyx

layer of polysaccharides that lies outside the cell wall in some bacteria

smooth er

That portion of the endoplasmic reticulum that is free of ribosomes; makes lipids

cyanobacteria

Photosynthetic, oxygen-producing bacteria (formerly known as blue-green algae).

fimbriae

small, bristle-like fibers that sprout from the cell surface

conjugation pili

rigid tubular structures used by bacteria to pass DNA from cell to cell

cytoskeleton

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

chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

endomembrane system

A network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles.

plastids

A group of membrane‐bound organelles commonly found in photosynthetic organisms and mainly responsible for the synthesis and storage of food.

cilia

short, hair-like structures made of microtubules that enable movement of cells or movement of materials outside a cell

flagella

Long, slender extension used for locomotion by some bacteria, protozoans, and sperm.