Lecture 9: Cell Structure & Function

Question 1

What are the points of the cell theory?

Answer 1

• Cells are fundamental units of life
• All living organisms are composed of cells
• All cells come from preexisting cells

Question 2

Prokaryotic Cells

Answer 2

(archea & bacteria)
- DNA is circular
- typically have a capsule (sugary coat)
- Nucleoid (where youll find DNA)
- Bacterial Cell Wall (gram negative & gram positive)
- No membrane-bound organelles

Question 3

Gram negative vs Gram positive

Answer 3

Gram Negative
- pink stain
- two membranes (inner more selective)

Gram Positive
- purple stain
- one membrane

Question 4

Bactria flagella vs Eukaryotic flagella

Answer 4

Bacteria
- made up of flagellin
- rotary movement
- powered by proton concentration
- Smaller

Eukaryotic
- bending movement
- powered by ATP
- Made of tubulin
- Larger

Question 5

Ribosome function & location

Answer 5

• Make proteins
• Can be found: on RER, mitochondria, chloroplasts, and free-floating in the cytoplasm

Question 6

Nucleus function (what is the nuclear lamina)

Answer 6

Stores genetic information (DNA), used as a pre-assembly of ribosomes, and controlls cell activity. Nuclear lamina allows for the shape of the nucleus and its attached to the nuclear inner membrane.

Question 7

What makes up the endomembrane system? And what are their functions?

Answer 7

Endoplasmic reticulum
SER: modification of small molecules, lipid synthesis, and calcium storage
RER: ribosomes, proteins folded, chemically modify

Golgi Apparatus
- Modifies, packages, and sorts proteins
- Add polysaccharides to proteins (glycosilation)

Question 8

What are lysosomes?

Answer 8

They serve in cellular digestion/recycling
- They contain hydrolytic enzymes
- Digestion of macromolecules to monomers
- Common in animal cells
- Execretion

Question 9

Mitochondria function and structure

Answer 9

Powerhouse of a cell (energy transformation)
The matrix: contains ribosomes, DNA, and enzymes for energy conversion
The Cristae: contains key molecules for the ATP generation from fuel molecules
The Inner Membrane: the primary barrier between the cytosol and mitochondrial enzymes

Question 10

Plastids

Answer 10

Chromoplasts - Store Pigments
Leukoplasts - Storage Organelles
Amyloplast - Stores Starch

Question 11

Membrane-enclosed organelles

Answer 11

Peroxisomes: degradarion of peroxides, oxidtion of fatty acids, synthesis of lipids
Glyoxysomes: only in plants, lipids converted to carbohydrates
Vacuoles: rise from ER to GA, storage for toxins and waste, digest germs, structure based off of turgor pressure

Question 12

3 different kinds of cytoskeleton

Answer 12

Microfilaments: muscle contraction, shape and support, and made up of actin, assemble from positive end

Intermediate filaments: anchor cell structures in place, nuclear lamina, desmosomes, made of fibrous proteins

Microtubules: internal cellular skeleton, tracks for motor proteins (kinesins and dyenins), nuclear division (mitotic spindle)

Question 13

Motor Proteins

Answer 13

Utilized for cellular transport (microtubules)
Kinesins - walks to positive
Dynein - walks to negative

Question 14

The Cell Wall

Answer 14

Function : support, barrier to infections, and plant form

• Animal : lack a cell wall
• Plants : made up of cellulose fibers embedded in polysaccharide and protein matrix (plasmodesmata used to connect plant cells together)
• Fungi : made up of chitin