Unit 4: Cell Biology

Characteristics of prokaryotic, eukaryotic, plant, animal, and bacteria cells as well as organelles' function

(1665) Hooke

• first to use the term “cell” to describe the structures that make up all living things

• observed cork cells (dead)

(1670’s) Leeuwenhoek

• father of modern microbiology

• first to observe living cells

Cell Theory

1. All organisms are composed of one or more cells

2. Cells are the basic units of structure and function for all living things

3. Cells arise only from other pre-existing cells

Prokaryotic cells

simplest, most ancient/oldest type of cell

Prokaryotic cells are found only in

bacteria

Two main things prokaryotic cells don’t have that eukaryotic cells do

a nucleus and “membrane-bound” organelles

Eukaryotic cells

more modern, complex cells

Eukaryotic cells are found in

plants, animals, fungi, and protists

Plant cells are what type of cell?

eukaryotic cells

Animal cells are what type of cell?

eukaryotic cells

Bacterial cells are what type of cell?

prokaryotic cells

What shape is a plant cell most likely to look like in a diagram?

a rectangle

What shape is an animal cell most likely to look like in a diagram?

an irregular shape (but rounded)

What object does a bacterial cell’s shape resemble?

a pill

Four main components needed to make a cell

cell membrane, cytoplasm, ribosomes, and DNA

Cell membrane is the same as

plasma membrane

Cytosol is the same as

cytoplasm

Function of the cell membrane

• outer boundary of the cell

• separates the cell from the external environment

• regulates what goes in and out of the cell (maintains homeostasis)

Function of cytosol (cytoplasm)

• clear fluid filling the cell in which organelles are suspended

• watery environment

Function of the nucleus

• contains genetic material

• controls cell activity

• surrounded by nuclear membrane

Function of nucleolus

• found within the nucleus

• site where ribosomes are made

Function of endoplasmic reticulum

• “intracellular highway” - intracellular means within the cell

• system of transport tubules within the cell - tubules mean small tubes

Difference in textures between endoplasmic reticulum with and without ribosomes

smooth = no ribosomes

rough = with ribosomes

Function of free-floating ribosomes

• location where proteins are assembled (amino acids join to make polypeptide)

• most numerous organelle

Function of golgi apparatus

• packaging and processing organelle

• proteins are modified and prepared for export

Analogy for golgi apparatus

a UPS store for cells

Function of mitochondria

• “powerhouse” of the cell

• location where ATP is made through aerobic respiration

Function of lysosome

• contains digestive enzymes

• breaks down food and worn-out cell parts

Analogy for lysosome

“trash disposal” + “digestion”

Function of peroxisome

• small, “membrane-bound”

• contains toxic peroxides that are safely broken down

Analogy for peroxisome

“nuclear waste dump” or “prison”

Function of cytoskeleton

provides shape and support for the cell

Cytoskeleton refers to which two protein strands?

microtubules and microfilaments

Function of vacuoles

storage organelle (stores material and waste)

Function of centrioles

aid in cell division

Function of the cell wall

• found outside the cell membrane

• usually made of cellulose (plants)

• provides support

Three plastids

chloroplasts, chromoplasts, and leucoplasts

Function of chloroplasts

• contain chlorophyll (green)

• site of photosynthesis

• where sunlight energy is converted to potential chemical bond energy (P.C.B.E.) in glucose

Function of chromoplasts

contain accessory pigments that aid in photosynthesis or sometimes just give color to plants

Function of leucoplasts

store starch

Cell membranes are found in

prokaryotic and eukaryotic cells

Cytosol (cytoplasm) is found in

prokaryotic and eukaryotic cells

Nucleus is found in

eukaryotic cells

Nucleolus is found in

eukaryotic cells

Endoplasmic reticulum (ER) is found in

eukaryotic cells

Free-floating ribosomes are found in

prokaryotic and eukaryotic cells

Golgi apparatus is found in

eukaryotic cells

Mitochondria is found in

eukaryotic cells

Lysosome is found in

eukaryotic cells

Peroxisome is found in

eukaryotic cells

Cytoskeleton is found in

eukaryotic cells

Vacuoles are found in

eukaryotic cells

Describe the vacuoles in animal cells

rare/small/several

Describe the singular vacuole in plant cells

large (holds water)

Centrioles are found specifically in

animal cells

Cell walls are found

specifically in plant cells and all prokaryotic cells

Plastids are found specifically in

plant cells

How do flagella help prokaryotic cells?

they assist in cell movement

Many prokaryotic cells have pili, which

aid in cell adhesion

The outside of a prokaryotic cell is called

a capsule

Prokaryotic cell walls are made of

peptidoglycan

Many prokaryotic cells carry DNA plasmids, which

often provide bacteria with genetic advantages, such as antibiotic resistance

Cell specialization

ex: epithelial, immune, sex, muscle, fat, bone, blood, nervous, and stem cell