Notes Cell Structure and Function

Cell – Smallest unit that can carry out all of the activities necessary for life

Number of Cells Organisms may be: Unicellular – composed of one cell Multicellular- composed of many cells that may organize

Cells May be Prokaryotic or Eukaryotic Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles Ex: bacteria Eukaryotes include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals)

A. Prokaryotes -have NO nucleus and no membrane bound organelles. Types of Cells A. Prokaryotes -have NO nucleus and no membrane bound organelles.

B. Eukaryotes -have a nucleus and membrane bound organelles i. Animal Cells ii. Plant Cells

Human cell Bacteria cell

Two Main Types of Eukaryotic Cells Animal Cell Plant Cell

Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

Differences between plant cells and animal cells Relatively smaller in size Relatively larger in size Irregular shape Regular shape No cell wall Cell wall present

Differences between Plant Cells and Animal Cells Vacuole small or absent Large central vacuole Glycogen as food storage Starch as food storage Nucleus at the center Nucleus near cell wall

Organ = A group of tissues with one or a few functions : heart, lung, stomach, liver, pancreas, skin, kidney, etc.) -elle = small or tiny Organelle = tiny organs

ORGANELLES FOUND IN BOTH ANIMAL AND PLANT CELLS

1. CELL MEMBRANE – “strainer or screen” (sac around the cell) a. Semi-permeable - Controls what enters & leaves the cell b. Protects cell & holds cell together

c. Made of phospholipids d. Also called the Plasma Membrane

(jelly-like material) 2. CYTOPLASM (jelly-like material) Supports cell parts Allows cell parts to move

3. NUCLEUS – “brain” Control center of the cell

3a. CHROMOSOMES Contains the DNA/genes that direct the making of proteins to make an organisms traits i. Means “colored bodies” ii. Chromatin is long thin invisible DNA iii. Chromosomes are short fat condensed visible DNA

3b. NUCLEOLUS Controls cell reproduction and makes ribosomes which make proteins

3c. NUCLEAR MEMBRANE Controls what enters and leaves the nucleus

5. VACUOLES – “storage boxes” (bubbles) a. Storage of food and water, wastes and enzymes b. Animal cells have many small ones while plant cells have one large one Plant Vacuole

6. ENDOPLASMIC RETICULUM “bus” (highway) a. Transport system in the cell b. Rough (with ribosomes) and smooth (none)

7. RIBOSOMES -Produce proteins for the cell

8. MITOCHONDRIA (powerhouse) a. Converts stored food into energy for the cell to use.

9. GOLGI BODY – “packaging plant” (post office) a. Package & exports protein from the cell Hair, finger nails are good examples of these proteins

ORGANELLES FOUND IN ONLY ANIMAL CELLS

ANIMAL CELLS ONLY 10. CENTRIOLE Small part of animal cell that helps in cell division

ANIMAL CELLS ONLY 11. LYSOSOME (stomach or garbage collector) a. Contain enzymes thatDigest or gets rid of worn out cell parts, bacteria or viruses b. Found in carnivorous plants

ORGANELLES FOUND IN ONLY PLANT CELLS

PLANT CELLS ONLY 12. CELL WALL (square) a. Made of Cellulose which makes plant stiff b. Supports plant and protects cell

13. CHLOROPLAST (green) a. Filled with the green pigment chlorophyll b. Makes chemical energy in the form of sugar from sunlight in the process called photosynthesis.

Plant Cell Smooth endoplasmic Vacuole reticulum (free) Chloroplast Nuclear envelope Ribosome (attached) (free) Smooth endoplasmic reticulum Nucleus Rough endoplasmic reticulum Nucleolus Golgi apparatus Mitochondrion Cell wall Cell Membrane Chloroplast Vacuole Plant Cell

Animal Cell (attached) Ribosome Nucleolus (free) Nucleus Cell Membrane Centrioles Nucleolus Nucleus Nuclear envelope Rough endoplasmic reticulum Golgi apparatus Smooth Mitochondrion Cell Membrane Ribosome (free) (attached) Animal Cell

Prokaryotes Eukaryotes Animal Cells Plant Cells Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell membrane Contain DNA Ribosomes Animal Cells Plant Cells Cell membrane Ribosomes Nucleus Endoplasmic reticulum Golgi apparatus Lysosomes Vacuoles Mitochondria Cytoskeleton Cell Wall Chloroplasts Centrioles