2.1 Cells

Cells

cell structure

Common Cell Traits

Cell membrane•outer covering of cell•made of one or more layers of linked molecules

Cytoplasm•inside every cell•gelatin-like•contains hereditary material that controls the life of the cell

comparing cells

nerve cells can be 1m long

human egg cell is no bigger than the dot on this i

human red blood cells is 1/10 the size of a human egg cell

bacterium are even smaller- 8000 can fit inside a human egg cell

cell types

PROKARYOTIC CELLSno membrane bound

structures

EUKARYOTIC CELLSmembrane-bound

structures

Cell Organization

cell wall

found in plants, algae, fungi, most bacteria

tough, rigid outer coverings that protect the cell and give

it shapeplant cell walls

are mainly made of

cellulose....which is?

what makes the cell walls rigid? Pectin and

lignin!

cell membrane

protective layer around all cellsif a cell has a cell wall, then

the cell membrane is

inside of it

what does it do? regulate interactions between the cell and the environment

water can move into and out of cell through the cell membrane

food particles and some molecules enter and waste products leave

through the cell membrane

cytoplasm

gelatinlike substance that fills cells which is constantly moving

contains a framework called the

cytoskeleton - this helps

maintain or change the

shape of the cell

cytoskeleton helps some cells move

cytoskeleton is made up of thin, hollow tubes of protein and thin, solid protein

fibers

organelles

contained within the cytoplasm

What do organelles do? ★process energy★manufacture substances needed by the cell★move materials★act as storage sites★are surrounded by membranes★nucleus is usually the largest organelle

nucleus

is surrounded by a membrane

directs all cell activities

DELI MANAGER

materials enter and leave through the membrane

contains

instructions for

everything in the

cell, which are

found on DNA

a nucleolus is also within the nucleus

energy-processing organelles

cells need energy to: ✤process food✤make new substances✤eliminate wastes✤communicate with each other

PLANTS๏food is made in green organelles called chloroplasts๏contain green pigment chlorophyll๏chlorophyll captures light energy that is used to make glucose

ANIMALS๏energy in food is stored until it is released by the mitochondria๏organelles where energy is released from the breakdown of food into carbon dioxide and water๏muscle cells are more active, so they contain more mitochondria

manufacturing organelles

proteins take part in nearly every cell activity

Proteins: •part of cell membrane•needed for chemical reactions that take place in the cytoplasm•are produced on small structures called ribosomes

ribosomes

considered an

organelle, but they do

not have a membrane

some float freely in cytoplasm, some attach to the endoplasmic reticulummade in the

nucleolus

receive directions from DNA on how,

when, and in what

order to make specific proteins

processing, transporting, and storing organelles

endoplasmic reticulum (ER) extends from the nucleus to the cell

membrane

a series of folded membranes

materials can be processed and moved around

inside of the cell

rough vs.

smooth

smooth ER process other cellular substances such

as lipids that store energy

Rough ER make proteins that are

moved out of the cell or used within the cell

golgi bodies proteins are made and sent

to the Golgi

bodies

Golgi bodies sort proteins and other cellular substances and

package them into membrane-bound structures called vesicles

vesicles deliver cellular substances to areas inside the cell

Refrigerator - cells have membrane-bound spaces called vacuoles for temporary

storage of materials (water, waste products, food, and other cellular

materials)

recycling organellesactive cells break down and recycle

substances

lysosomes contain digestive chemicals

that help break down food

molecules, cell wastes, and worn-

out parts

lysosome membrane keeps the chemicals from leaking into the

cellwhen a cell dies a lysosome’s membrane

disintegrates, releasing digestive chemicals that quickly breakdown the

cell’s contents

organ system

tissue

cell