CHAPTER 2

.1

TH

E C

EL L

OPEN SYSTEM

Cells are open systems (can exchange matter and energy with their surroundings)

Cells perform the following life processes… Intake of nutrients Movement Growth Response to stimuli Exchange of gases Waste removal Reproduction

CELL MEMBRANE

Protective barrier for the cell

Allows transport of materials (needed/waste

Cell communication

NUCLEUS

Contains DNA

Directs all cell

activity

CYTOPLASM

Gel-like substance inside the cell membrane

Contains nutrients

Holds organelles

Cytoplasmic streaming (movement of molecules)

CELL WALL

In plants, bacteria, protists, and fungi

Rigid frame that supports the cell

CHLOROPLAST

Found only in plants and protists

Contain chlorophyll (green pigment)

Site of photosynthesis

VACUOLES AND VESICLES

Store nutrients, fats

Central vacuole in plants stores water

Turgor pressure increases as it takes in water, making the cell turgid

ENDOPLASMIC RETICULUM

Small tubes branching from the nucleus

Materials are transported through it

Rough ER has ribosomes for protein synthesis

Smooth ER – fat and oil production

LYSOSOMES

Sacs where digestion happens

Defense against bacteria

Destroy damaged organelles

GOLGI APPARATUS

Receives substances from ER to package and transport out of the cell

MITOCHONDRIA

Where cellular respiration takes place

I MISSED TWO

I missed two Organelles. What are they? What do they do?

SEE PAGE 270 – COMPARE PLANT AND ANIMALSimilarities

cell membrane

cytoskeleton made up of proteins and lipids

DNA

Differences

Animals – centrioles

-specialized molecules (hemoglobin/cholesterol)

-glycogen – energy

Plants – cell wall (cellulose)

-starch/oils for energy

-central vacuole

-chloroplasts (chlorophyll)

CHEMICAL COMPOSITION OF CELL STRUCTURES4 major organic compounds…

-lipids (fats/oils)

-carbohydrates (sugars)

-proteins (muscle fibre)

-nucleic acids (DNA)

Water is the other major compound (solvent)

Trace elements

Mg

Zn

Mn

Fe

MODEL OF CELL MEMBRANE

Plasma membrane

Maintains equilibrium inside cell

Phospholipid bilayer

Fluid mosaic model – first suggested in 1972

Proteins suspended in membrane – outside, inside, throughout