Cell, Endomembrane system, mitochondria, chloroplasts

Question 1

Prokaryotes

Answer 1

• Live any environment
• oxidize anything
• greatest metabolic diversity
• much smaller than eukaryotes (no nucleus)

Question 2

Eukaryotes

Answer 2

• nucleus

- compartmentalization

Question 3

Plant cell

Answer 3

• cell wall
• chloroplasts
• modified lysosome called vacuole
• cell wall means they don’t need sodium potassium pumo

Question 4

Nucleus

Answer 4

• assembled ribosome subunits and mRNA are transported through nuclear pores to cytoplasm

Question 5

Nuclear proteins

Answer 5

• like transcription factors are brought into nucleus through nuclear pores

Question 6

Rough ER

Answer 6

• ribosomes attached to outside, they become attached when they start translating a membrane protein. Then the secreted proteins are released into the ER lumen.

Question 7

Smooth ER

Answer 7

• membrane lipids

- detoxification, usually means oxidation

Question 8

Golgi

Answer 8

• stack of membranes generated by vesicles coming from ER and fusing cis face, other vesicles budding off trans
• while the proteins and lipids are in golgi, they are further modified (side chains added, proteins sorted)
• distribution centre (come from ER and move on to cell membrane)

Question 9

Endocytosis

Answer 9

• molecules that need to be transported are recognized by receptors and initiate endocytosis
• budding off vesicle into interior of cell. Now endosome fuses w/ other vesicles carrying special digestive enzymes and proton pumps, until endosome because lysosome w/ low pH where contents are digested and released to cytosol.

Question 10

Autophagy

Answer 10

Self eating

Question 11

Mitochondria

Answer 11

• powerhouse of the cell
• space enclosed by inner membrane in matrix
• citric acid cycle occurs in matrix
• respiratory enzymes are integral membrane proteins located inner membrane

Question 12

Chloroplasts

Answer 12

• photosynthesis
• Carbon fixation occurs in stroma
• space enclosed by inner membrane in chloroplasts

Question 13

Cristae

Answer 13

Maximizes area for inserting membrane proteins

Question 14

Thylakoids

Answer 14

• in chloroplasts, light reactions of photosynthesis takes place in stacks of membranes called thylakoids

Question 15

What evidence shows chloroplasts + mitochondria are decendents of bacteria?

Answer 15

• double membrane
• own genome, w/genes more similar to bacteria genes and own ribosomes similar to bacterial ribosomes
• unique system for protein + lipids, which may show they evolved separate

Question 16

Cytoskeleton

Answer 16

• structural elements important for all shape + movement (actin filaments + microtubules)

Question 17

Actin filaments

Answer 17

• polar w/ plus minus end
• polymerize and depolymerize from monomers through non-covalent protein-protein interactions
• responsible for cell shape and changes

Question 18

What do actin filaments and myosin mediate? How does it work?

Answer 18

• muscle contraction
• cell shape changes
• cytoplasmic streaming and cytokinesis
• it works because myosin II forms bipolar complexes w/ myosin heads at opposite ends. They walk towards ends, and it leads with contraction.

Question 19

Microtubules (MT’s)

Answer 19

• component of cytoskeleton
• bigger, form cylinder of alpha beta tubulin dimers
• polar w/ plus and minus ends
• microtubule binding proteins that regulate growth or shrinkage of microtubules
• vesicles move along MT to destrination and MT move chromosomes during division

Question 20

What are the two different motor proteins?

Answer 20

• Kinesin (one direciton)

- Dynein (other direction)

Question 21

Cilia

Answer 21

• beat back and forth, found of cells lining lungs, remove debris, in oviduct, on single celled oviduct

Question 22

Flagella

Answer 22

• longer, on sperm

- sliding results in bending of cilia or flagella

Question 23

Intermediate filaments

Answer 23

• no polarity, do not polymerize or depolymerize
• additional strength to cells (keratin) or nucleus
• form rope-like structures via coiled coils

Question 24

ECM (extra cellular matrix)

Answer 24

• fills structural roles (tendons in cartilage which consists of collagen (a coiled protein))

Question 25

How do cells attach to environment?

Answer 25

- transmembrane protein integrin binds to ECM via adaptor proteins to actin cytoskeleton

Question 26

Focal adhesions

Answer 26

- adhesion sites found on basal side | - attach muscles to bones, via tendons

Question 27

How can cells be attached to other cells?

Answer 27

- epithelium is sheet of cells - has two diff sides - apical (towards) - basolateral (interior)

Question 28

Tight junction

Answer 28

- seals cells together, preventing passage

Question 29

Gap junctions

Answer 29

- create channels that connect cells in some animal tissues