Chapter 7 Section 3

CELL STRUCTURES & ORGANELLES

CYTOPLASM

Occurs inside the plasma membrane

Fluid portion of the cell

CYTOSKELETON

Is a supporting network of long, thin protein fibers that form a framework for the cell and provide an anchor for the organelles inside the cell

NUCLEUS

Isolated region where the DNA is

Double membrane allowing for DNA to carry out its functions and not be affected by processes occurring in other parts of the cell

Without a nucleus, a cell cannot reproduce. Loss of reproductive ability is often paired w/increased specialization Human red blood cells do not

have a nuclei; they are specialized to transport oxygen

RIBOSOMES

Structures found free in the cytoplasm or attached to the ER

Always composed of a type of RNA and protein

Carry out protein synthesis

ENDOPLASMIC RETICULUM

Extensive network of tubules or channels that extends almost everywhere in the cell

Transportation of material throughout the internal region of the cell

Two kinds of ER: Smooth & Rough

SMOOTH ER Has unique enzymes

embedded

Production of membrane phospholipids and cellular lipids

Production of sex hormones (testosterone & estrogen)

ROUGH ER

Has ribosomes on the exterior of the channels

Protein synthesis– protein development and transport

Proteins might become parts of membranes, enzymes, or even messenger cells

GOLGI APPARATUS Appears to be flattened sacs called cisternae,

which are stacked on top of one another

Function in the collection, packaging, modification, and distribution of materials synthesized in the cell

VACUOLES

Occupy a very large space in the cell

Provide storage (food, wastes, water)

Vacuoles enable cells to have higher surface area to volume rations

Uptake of water in plants that provide rigidity for the organism

LYSOSOMES

Intracellular digestive centers that arise from the Golgi apparatus

Sacs bounded by a single membrane that contain as many as 40 different enzymes

Enzymes also digest bacteria and viruses that have entered the cell

Lysosomes also bond with older or damaged organelles from with and help recycle them

CENTRIOLES Are organelles

made of microtubules that function during cell division

Located in the cytoplasm of animal cells near the nucleus

MITOCHONDRIA Rod-shaped

organelles that appear throughout the cytoplasm

Involve the production or usable cellular energy called ATP “cell powerhouse”

CHLOROPLASTS

occur only in algae and plant cells Capture light energy and convert

it to chemical energy through a process called photosynthesis

Also contains grana, thylakoids, and stroma

Thylakoids are flattened membrane sacs w/ components necessary for the absorption of light

CELL WALL

Only found in plant cells

The cell wall is a thick, rigid, mesh of fibers that surrounds the outside of the cell membrane

Provides protection and support

CILIA AND FLAGELLA

Cilia are short, numerous projections that look like hair

Flagella are longer and less numerous

Both are used for locomotion (movement)

PLANT VS. ANIMAL

Plant Cells Nucleus present

Cell wall present

chloroplasts

Animal Cells Nucleus present

Cell wall missing

Chloroplasts missing