Cell Structure & Function · Cell Structures & Organelles Author: Hazleton Area School...

Cell Structure &

Function Sections 7-2 and 7-3

Eukaryote vs. Prokaryote

eukaryotes: organisms

whose cells contain a nucleus

prokaryotes: organisms

whose cells lack a nucleus

a tiny

structure that

performs a

specialized

function in the

cell

area between

the nucleus

and the cell

membrane

where the

organelles are

found

yes no

yes yes

yes yes

yes no

both unicellular

plants, animals, fungi, protists

bacteria

A. Boundary Structures

Cell Wall

Location: outside the cell

membrane

Function: helps to protect

& support the cell

A. Boundary Structures

Cell Wall

found in cells of

plants, algae, and

some bacteria

made of cellulose

and lignin

A. Boundary Structures

Cell Membrane Function: regulates what

enters and leaves the cell. Also aids in protection and support of the cell.

Made of lipids with associated proteins and carbohydrates.

Structure of the Cell

Membrane

B. Nucleus

organelle that controls the cell’s

activities and contains DNA

Nuclear envelope

(membrane): two membranes

that form the boundary around

the nucleus

B. Nucleus

Nucleolus:

where ribosomes are made

made of RNA and proteins

Chromatin:

DNA bound to protein

Spread throughout the nucleus

Chromosomes:

Distinct structures in nucleus that contain the genetic info that must be passed to each new generation of cells

C. Energy Producing Organelles

change the chemical energy stored in food into compounds that are more convenient for the cell to use

have a degree of independence from the rest of the cell

C. Energy Producing Organelles

trap the energy of sunlight and

convert it into chemical energy

found only in plant cells & algae

have a degree of independence from the rest of the cell

D. Transport/Homeostasis

Ribosomes

structures in which proteins are made

composed of RNA & protein

some are attached to membranes (rough ER); others are free in the cytoplasm

D. Transport/Homeostasis

Endoplasmic Reticulum

(er)

complex network of sacs that

transport materials in the cell

2 types:

smooth er

rough er

D. Transport/Homeostasis

Smooth er

walls of the sacs look smooth

stores special chemicals and

enzymes

D. Transport/Homeostasis

Rough er

involved in synthesis of

proteins

has ribosomes stuck to

surface (make it look “rough”)

chemically modifies proteins

D. Transport/Homeostasis

Golgi apparatus (body)

looks like a flattened stack of

membranes (pancakes)

modifies, collects, packages,

& distributes molecules made

at one location of the cell and

used at another

Golgi apparatus

D. Transport/Homeostasis

Lysosomes

contain chemicals & enzymes

necessary for digesting certain

materials in the cell

the “clean-up crew”

not in plant cells

D. Transport/Homeostasis

Vacuoles

saclike storage structures

store water, salts, proteins,

and carbohydrates

plants have a large central

vacuole to store excess water

D. Transport/Homeostasis

Plastids

store food and pigments

3 examples

chloroplasts: store chlorophyll

leukoplasts: store starch

chromoplasts: store pigment molecules

E. Framework

Cytoskeleton

variety of filaments and

fibers that support cell

structure and drive cell

movement

composed of microtubules and

microfilaments

Cytoskeleton

E. Framework

Microtubules

hollow tubes

aid in support and movement

Cilia: short, thread-like

Flagella: long, whip-like

Centrioles Located near the nucleus

Help organize cell division

Not found in plant cells

E. Framework

Microfilaments

long, thin fibers

movement & support

movement of cytoplasm