Cell Anatomy

Plasma Membrane (Cell Membrane)

The thin, flexible outer boundary that separates the living cell from its external environment

Phospholipid bilayer with embedded proteins

What is the plasma membrane made of?

Nucleus

Largest organelle, usually 1 per cell

Nuclear Envelope

The phospholipid double membrane that separates the contents of the nucleus from the cytoplasm

Nuclear Pores

Bumps all around the nuclear envelope that regulate flow of molecules back and forth, they also connect the nucleoplasm to the cytoplasm

Chromosome (chromatin)

DNA wrapped around proteins, carries genes that control traits and protein production

Nucleolus

Region inside nucleus where ribosomes are assembled from RNA and proteins

Endomembrane System

Consists of internal membranes and organelles in eukaryotic cells to work together to modify, package, and transport lipids and proteins

Nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vesicles, vacuoles, plasma membrane, peroxisome

Which organelles does the endomembrane system include?

Endoplasmic Reticulum

Systems of membranes forming a network of sacs and canals, wind back and forth to carry proteins and other substances to other areas of the cell

Rough ER

Network of membranes covered in ribosomes, synthesizes and modifies proteins that will be sent out of the cell or to the membrane, also makes phospholipids for cellular membranes

Smooth ER

Has few or no ribosomes, synthesis of carbohydrates, lipids, steroid hormones. Detoxification of medications and poisons, may store calcium for muscle cells

Vesicle

Small, membrane-bounded sac that stores substances within a cell. Protect cargo and keep it separate from the rest of the cytoplasm

Golgi Apparatus

Series of flattened membranes that process, package, and send out modified proteins

Lysosome

Vesicle that digests macromolecules and even worn out organelles, contains digestive enzymes

Peroxisome

Small enzyme-filled vesicle with a single membrane. Contains reactions that break down fatty acids and amino acids, may detoxify poisons

Vacuole

Membrane stores sac, usually for storage

Central Vacuole

Large vacuole in the plant cell that occupies most of the area of the cell, helps regulate water concentration under changing environmental conditions

Plastids

Organelles found in plants and algae. Have a double membrane, store or make key molecules

Chromoplast, leucoplast, chloroplast

What are the 3 main types of plastids?

Chromoplast

Plastid that stores pigment for color

Leucoplast

Plastid that stores starch and other nutrients

Chloroplast

Plastid that carries out photosynthesis, makes glucose, has a doble membrane, has its on 70S ribosomes

Thylakoids

Flat, disk-shapes membranes inside chloroplasts that contain chlorophyll and other pigments

Thylakoid Membrane

The outer surface of each thylakoid disk. Contains chlorophyll and other pigments, houses the structures needed for capturing light energy in photosynthetic organisms

Granum (plural: grana)

Stack of thylakoids

Stroma

The gel-like fluid that fills the inside of the chloroplast. Surrounds the thylakoids, contains enzymes, DNA, and ribosomes

Chlorophyll

The green pigment found in chloroplasts. Located in thylakoid membranes, absorbs light energy needed for photosynthesis

Nucleoplasm

Thick, sticky liquid that fills the nucleus of the cell

Mitochondrion (plural: mitochondria)

Site for conversion of stored energy (macromolecules) into more usable form (ATP)

Cristae

Folding of the inner membrane of the mitochondrion

Mitochondrial Matrix

Area in the mitochondria that is enclosed. Contains enzymes, DNA, and ribosomes

Cytoskeleton

Network of protein fibers with several functions: helps maintain cell shape, holds some organelles in specific positions, allows movement of cytoplasm + vesicles within the cell, enables cells within multicellular organisms to move

Ribosomes

Assemble amino acids into proteins, made of rRNA and proteins

Microfilaments (actin filaments)

Protein fibers that play a role in cell division and shape, involved in movement in cell and body

Intermediate Filaments

Protein fibers that provide stability of shape

Microtubules

Protein cylinders that move organelles

Centriole

Cylinder made up of 9 triplets of microtubules

Centrosome

2 centrioles that are on top of each other

Cilia

Short, hairlike projections from the plasma membrane. Aid in movement of cell, line trachea and gastro-intestinal tract

Flagella

Long, slender extension used for locomotion by some bacteria, protozoans, and sperm. Single projection from cell surface

Cell Wall

Cellular structure that surrounds a plant, protistan, fungal, or bacterial cell and maintains the cell’s shape and rigidity. Composed of polysaccharides

Eukaryotic Cells

Cells that possess a membrane-bound nucleus and various membrane-bound organelles

Prokaryotic Cells

Simple, single-celled organisms defined by the absence of a membrane bound nucleus and other membrane-bound organelles

Archeans

Unicellular, prokaryotic organisms that were originally classified as bacteria but are now recognized as a separate domain

Bacillus

A rod-shaped bacterium

Coccus

A spherical-shaped bacterium

Spirilla

A spiral shaped or curved bacteria (rigid)

Spirochetes

Long, slender spiral or corkskrew-shaped flexible bacteria

Cell Envelope

The collective layers that form the outer boundary of a bacterial cell (includes plasma membrane and cell wall)

Mesosomes

In bacteria, plasma membrane that folds into the cytoplasm and increases surface area

Glycocalyx

Gel-like layer outside the cell wall of a bacterium and animal cells

Capsule

A form of glycocalyx that consists of a gelatinous layer; found in algae and some bacteria

Slime Layer

A form of glycocalyx that is diffused

Nucleioid

Region of prokaryotic cells where DNA is located; it is not bounded by a nuclear envelope

Plasmids

Extrachromosomal ring of accessory DNA in the cytoplasm of prokaryotes

Cyanobacteria

Photosynthetic bacterium that contains chlorophyll and releases oxygen

Fimbriae

Small, bristlelike fiber on the surface of a bacterial cell, which attaches bacteria to a surface

Conjugation Pili

In bacteria, elongated, hollow, appendages used to transfer DNA to other

Organelle

Small, membranous structures in the cytoplasm having a specific structure and function

Polyribosome

Part of the endomembrane system that is a complex of multiple ribosomes simultaneously making the same protein