bio 2 2nd exam (TOUR OF THE CELL)

Question 1

Eukaryotic functions

Answer 1

• Manufacture
• Breakdown
• Energy processing
• Support, movement, and communication between cells

Question 2

Cytosol

Answer 2

contains many metabolic pathways, protein synthesis

Question 3

Nucleus

Answer 3

contains main genome, DNA and RNA synthesis

Question 4

Endoplasmic reticulum (ER)

Answer 4

-synthesis of most lipids, synthesis of proteins for distribution to many organelles and to the plasma membrane

Question 5

Golgi apparatus

Answer 5

-modification, sorting, and packaging of proteins and lipids for either secretion or delivery to another organelle

Question 6

Lysosomes

Answer 6

intracellular degradation

Question 7

Endosomes

Answer 7

sorting of endocytosed material

Question 8

Mitochondria

Answer 8

-ATP synthesis by oxidative phosphorylation

Question 9

Peroxisomes

Answer 9

oxidation of toxic molecules

Question 10

§Localization of ER and Golgi depends on microtubule array

Answer 10

ØIf microtubules are disrupted the Golgi apparatus fragments and disperses and the ER network collapses toward the cell center

Question 11

Proteins Are Imported via diff mechanisms

Answer 11

•Localization fate depends on amino acid sequence which can contain sorting signals

–Most proteins do not have sorting signals so they are localized to the cytosol

–Mitochondria and plastids contain their own ribosomes which synthesize proteins specific for that organelle

Question 12

GATED TRANSPORT (IMPORTANT)

Answer 12

–Protein traffic between nucleus and cytosol

–Nuclear pore acts as a gate

Question 13

TRANSMEMBRANE TRANSPORT IMPORTANT

Answer 13

–Membrane bound protein translocators directly transport proteins across a membrane

–Cytosol->ER, mitochondria, chloroplast

–Transported protein is usually unfolded

Question 14

VESICULAR TRANSPORT IMPORTANT

Answer 14

–Membrane-enclosed transport intermediates

• Vary in size
• Ferry proteins from one compartment to another

Question 15

Epigenetic information

Answer 15

–Epigenetic information in the form of at least one distinct protein that preexists in the organelle membrane is also required

• –ER cannot be made without a preexisting ER or a membrane that specifically contains the ER-specific protein translocators.

Question 16

Components of the endomembrane system

Answer 16

–Nuclear envelope

–Endoplasmic reticulum

–Golgi apparatus

–Lysosomes

–Vacuoles

–Plasma membrane

The components are either continuous or connected via transfer by vesicles

Question 17

components of neucleus

Answer 17

• dna
• nuclear envelope
• nuclear lamina
• nucleolus
  
  • house the genetic material (dna)
  • rna replication
  • rna synthesis

Question 18

Inner nuclear membrane

Answer 18

•Specific proteins that act as binding site for chromatin and for the nuclear lamina

Question 19

•Outer nuclear membrane

Answer 19

• Continuous with ER membrane
• Studded with ribosomes

Question 20

•Perinuclear spac

Answer 20

•Perinuclear space is continuous

With ER lumen

Question 21

endoplasmic reticulum

Answer 21

The endoplasmic reticulum (ER) is a system of membranous channels and saccules.

Question 22

Rough ER

Answer 22

Rough ER is studded with ribosomes and is the site of protein synthesis and processing. “Membrane factory of the cell”

Protein synthesis on ribosomes attached to ER membrane:

secreted proteins

integral membrane protiens

soluble proteins destined for life

in a membrane bound compartment

Question 23

Smooth ER

Answer 23

Smooth ER

synthesized lipids

Metabolized carbohydrates

Detoxifies poison

Stores calcium (sarcoplasmic reticulum)

Question 24

ER Signal Sequences

Answer 24

• When ER signal sequence emerges from ribosome, it directs the ribosome via SRP to a translocator on the ER membrane
• Forms a pore in the membrane

•Polypeptide is translocated

•Signal sequence is clipped off by a signal peptidase

•Growing polypeptide chain in lumen is bound by chaperones

•Mature protein is released into lumen of ER