Ch 4: Cell Structures

Essential Questions:

How is the structure of the

cell related to function?

How do cell malfunctions

result in pathologies?

4.1 Studying Cells

*Review the different types of

microscopes and how they are used

to view cells. See Microscope Movie

CYTOLOGY = study of cells.

CYTOTECHNOLOGIST =

professional who studies cells and

determines if cells are abnormal;

PAP test

Normal PAP

Abnormal PAP

Cell Theory

Robert Hooke, “Micrographia”

Anton van Leeuwenhoek, “Animalcules”

Schleiden and Schwann

1. All living things are composed of cells

2. Cells come from other cells

3. The cell is the basic unit of life

Cell Size

Cell Size

Surface area and volume are

limiting factors for cell size.

As cells grow too large, the

membrane can’t transport

enough materials.

Prokaryote Cells

Does not contain a membrane

bound nucleus; smaller than

eukaryotic cells

Domain: Bacteria & Archaea

All cells have:

Cytosol, Plasma membrane,

ribosomes, DNA

Eukaryotic Cells

Main Features

Membrane-bound

nucleus with

chromosomes

Various organelles that

perform specific

functions.

Liquid interior is the

cytoplasm (cytosol)

Endosymbiosis Theory

Provides a possible

explanation for the

origin of eukaryotic

cells, particularly

the mitochondria

and chloroplasts.

Plasma Membrane

Phospholipid bilayer with embedded proteins

The Nucleus

Nuclear Envelope

Nucleoplasm

Nucleolus - makes ribosomes

Chromosome (chromatin, DNA) - information storage

Ribosomes

Site of protein synthesis

Floats in cytoplasm and

found attached to

endoplasmic reticulum

mRNA provides the code

to build a chain of amino

acids

Mitochondria

“Powerhouse” of the cell

Provide energy in the form

of ATP

Specifically, they are

responsible for

CELLULAR

RESPIRATIONHas mitochondrial DNA that is separate from the cell’s

DNA. Endosymbiosis theory suggests that eukaryotes

evolved from prokaryotes and that the mitochondria was

once a free-living prokaryote.

What happens if your mitochondria don’t work?

1. Inner Membrane 2. Outer Membrane

3. Cristae 4. Matrix

Peroxisomes

Small organelles that carry out

oxidation reactions

Enzymes within them safely break

down hydrogen peroxide.

Lysosomes

Found in animal cells, known as the “garbage disposal” because

they break down substances (digestion)

GM2 ganglioside enters the nerve cell

as a source of food. Lysosomes

contain an enzyme, Hex-A that

digests GM2. Children with Tay-

Sachs lack Hex-A, so the GM2 builds

up within the cell and eventually kills

it.

Ellie’s Story | Cure Tay-Sach’s Foundation

Vesicles and Vacuoles

Used for storage and transport.

Vesicles can fuse with the

membrane and transport

materials out of the cell.

Plants have a large CENTRAL

VACUOLE

Centrosomes (Centrioles)

Move chromosomes during cell division

*Animal cells only

Chloroplasts

Plant cells only - site

of photosynthesis

Like the mitochondria,

also has its own DNA

Cell Wall

Only found in plant cells

Rigid structure made of

peptidoglycan and cellulose

This make plants difficult to

digest

4.4 Endomembrane System

A group of organelles that work to

process, package and secrete

proteins.

Ribosomes make the proteins

Endoplasmic reticulum transports

proteins (smooth vs rough)

Golgi Apparatus packages & exports

(like a post office)

4.5 The Cytoskeleton

Network of fibers that gives support and structure to the cell:

Microfilaments / Microtubules / Intermediate Filaments (maintain shape)

Cilia and Flagella

function in movement

Actin / Movement

The Big Picture

a. ________________

b. ________________

c. _________________

d. _________________

e. _________________

f. __________________

g. __________________

f. g.