Cell structure + function

Question 1

What is the relationship between the size of cells and the surface area to volume ratio?

Answer 1

When a cell gets larger the surface area to volume ratio decreases

Question 2

What is one special adaptation to increase surface area?

Answer 2

microvilli

Question 3

What are the two taxonomic domains of prokaryotic cells?

Answer 3

Bacteria
Archaea

Question 4

Explain the structure and function of a cell envelope. (Bacteria)

Answer 4

Plasma membrane- Lipid bilayer with imbedded proteins- forms mesosomes
Cell wall maintains shape of cell- strengthened by peptidoglycan
Glycocalyx- Layer of polysaccharides on the outside of the cell wall

Question 5

Explain the structure and function of the cytoplasm (bacteria)

Answer 5

Semifluid solution
Bounded by plasma membrane
Nucleoid- contains single, circular DNA molecule
Plasmids small accessory rings of DNA

Question 6

Explain the structure and function of the appendages (bacteria)

Answer 6

*Flagella provides motility
* Fimbriae - small, bristle-like fibres that sprout from the cell surface
* Sex pili - rigid tubular structures used to pass DNA from cell to cell
Bacterial Cell Structure

Question 7

What are the different types of eukaryotic cells?

Answer 7

Protists
Fungi
Plants
Animals

Question 8

What are the features specific to eukaryotic cells?

Answer 8

-Membrane bound nucleus that houses DNA
-Specialised organelles
-Plasma membrane
-Much larger than prokaryotic cells

Question 9

Draw and label a bacterial cell

Answer 9

See diagram
Key features:
Ribosome, Inclusion body, Mesosome, Fimbriae, Conjugation pilus, nucleoid, plasma membrane, cell wall, glycocalyx, flagellum

Question 10

What is the function of the following features of a bacterial cell:
Ribosome?
Inclusion body?
Mesosome?
Fimbriae?
Conjugation Pilus?
Nucleoid?
Cell wall?
Glycocalyx?
Flagellum?

Answer 10

Ribosome- site of protein synthesis
Inclusion body- stored nutrients for later use
Mesosome- Plasma membrane folding into cytoplasm to increase surface area
Fimbriae- Hairlike bristles allow adhesion to surfaces
Conjugation pilus- elongated hollow appendage used for DNA transfer to other bacterial cells
Nucleoid- location of bacterial chromosome
Cell wall- supports, shapes, protects
Glycocalyx- Gel coating outside cell wall, if compact called capsule, if diffuse called slime layer.
Flagellum- rotating filament present in bacteria to push cell forward

Question 11

Draw and label an animal eukaryotic cell.

Answer 11

See diagram

Question 12

Structure and function: Nucleus

Answer 12

Nucleus- (nuclear pores, nucleolus, nuclear envelope), Most of cells genetic material

Question 13

What are peroxisomes and what is their function?

Answer 13

Similar to lysosomes, membrane bound vesicles, enclose enzymes, enzymes synthesised by ribosomes instead pf ER.
Active in lipid metabolism, catalyse reactions that produce hydrogen peroxide (H2O2), toxic so broken down into water and O2 by catalase.

Question 14

Describe the structure and functions of mitochondria?

Answer 14

Contains ribosomes and own DNA, surrounded by double membrane, inner membrane surrounds matrix (inner semifluid containing respiratory enzymes) and folds to form cristae.
Breaks down carbohydrates, involved in cellular respiration, produces ATP.

Question 15

Explain the endomembrane system (4 points)

Answer 15

Proteins produced in the rough ER and lipids from smooth ER carried in vesicles to golgi apparatus
Golgi apparatus modifies and packages them into vesicles- go to cell destinations
Secretory vesicles carry them to membrane- exocytosis produce secretions
Lysosomes fuse with incoming vesicles and digest macromolecules.

Question 16

Structure and function: Lysosomes

Answer 16

Intracellular digestion
Releases nutrients
Breakdown of waste

Question 17

Structure and function: Golgi

Answer 17

Receives and modifies
Directs new materials

Question 18

Structure and function: Endoplasmic reticulum

Answer 18

Rough ER- Cell membrane and exported material, modifies proteins, intracellular transport.
Smooth ER- No ribosomes, makes lipids, intracellular synthesis pathways.
Ribosomes- Translates mRNA into a polypeptide chain.

Question 19

Draw and label a cell membrane

Answer 19

see diagram

Question 20

What is a glycoprotein?
What is a glycolipid?

Answer 20

Protein with carbohydrate attached
Lipid with carbohydrate attached

Question 21

What are the functions of the cytoskeleton?

Answer 21

Maintain cell shape
Assists in movement of cell and organelles
Assemble and disassemble as needed

Question 22

Structure and function: Actin filaments

Answer 22

• Extremely thin filaments, maintain cell shape
• Intracellular traffic control and movement
• Cytoplasmic streaming
• Important component in muscle contraction (with myosin)

Question 23

Structure and function: Intermediate filaments

Answer 23

• Intermediate size between actin filaments & microtubules
• Rope-like assembly of fibrous polypeptides
• Vary in nature from tissue to tissue and time to time
• Support nuclear envelope
• Cell-cell junctions, like those holding skin cells tightly together

Question 24

Structure and function: Microtubules

Answer 24

• Hollow cylinders made of two globular proteins called a and b tubulin, in dimers
• Form centrosome and centrioles (mitotic spindle)
• Interact with proteins kinesin and dynein to cause movement of organelles

Question 25

What are the main differences between prokaryotic and eukaryotic cells?

Answer 25

Prokaryotic- unicellular, smaller, no nucleus or membrane bound organelles, no cytoskeleton, circular DNA (1 chromosome), cell wall, divides by binary fission. Eukaryotic- Multicellular, Larger, nucleus + membrane bound organelles, cytoskeleton, multiple chromosomes linear DNA, cell wall only present in plants and fungi, divides by mitosis.