6 - Cell Structures & Function

Question 0

The nuclear envelope, what is it’s purpose? And is it single membrane, or double?

Answer 0

encloses the nucleus

Double membrane

Question 1

What is stored in the nucleus?

Answer 1

Chromosomes & information storage

Question 2

Define the nuclear lamina

Answer 2

it is the fibrous protein shell - strengthens the structure and maintains it’s shape
on the interior chromosomes attach to it

Question 3

What is in the nucleolus?

Answer 3

Where RNA molecules found in ribosomes are made + small and large ribosomal subunits are made

Question 4

What is the endoplasmic reticulum?

Answer 4

“inside formed network”

it extends from the nuclear envelope into the cytoplasm

Question 5

What is different between the rough endoplasmic reticulum and the smooth endoplasmic reticulum?

Answer 5

rough ER - purpose is to synthesize proteins

smooth ER - purpose is to catalyze reactions involving lipids

Question 6

Describe what the rough endoplasmic reticulum does

Answer 6

makes proteins for - plasma membrane, secreted into the cell exterior, or shipped to an organelle

the ribosomes on the exterior manufacture the proteins the then move inside on the lumen to undergo folding

Question 7

What are the functions of some of the proteins produced by the rough ER?

Answer 7

• carry messages out to other cells
• act as membrane transport proteins or pumps
• enzymes

Rough ER products are packaged up and shipped out

Question 8

The smooth endoplasmic reticulum - what is the purpose?

Answer 8

• contains enzymes that catalyze reactions w/ lipids
• could break down lipids
• manufacturing site for phospholipids used in plasma membranes
• reservoir for calcium ions that act as signaling

Question 9

What is the purpose of the cytoskeleton?

Answer 9

to hold the shape

long polymers of globular proteins

Question 10

What is the most prominent cell in bacteria?

Answer 10

Chromosome

Question 11

What is the purpose of ribosomes?

Answer 11

to manufacture proteins

Question 12

Describe a periosome

Answer 12

single membrane
originates from the ER
contains transporters for macromolecules
Function: oxidizes FA (H2O2)
Said to contain: catalase

Question 13

Describe the Golgi apparatus

Answer 13

for folding and finishing of proteins
cis side close to RER, receiver bay for Proteins from RER
trans surface -> plasma membrane, shipping bay

Question 14

The smooth ER - describe

Answer 14

contains enzymes to catalyze lipids
manufacturing site for phospholipids -> cell membrane
Reservoir for CA ions
has no ribosomes

Question 15

Describe glyoxysomes

Answer 15

in plants

oxidizes fats for storage

Question 16

Describe Lysosomes

Answer 16

Single membrane
contains protein pump
maintains a pH of 5.0 
acid hydrolases
function: digestion & recycling -> monomers
autophagy & phagocytosis

Question 17

define phagocytosis

Answer 17

“eat cell act”

a membrane surrounded package delivers to the lysosome to breakdown contents

Question 18

define autophagy

Answer 18

“same eating”

breaking down damaged organelles

Question 19

Does the mitochondria have a single or double wall?

Answer 19

double

Question 20

Which organelle carries it’s own chromosomes allowing it to make it’s own genes?

Answer 20

the mitochondria

Question 21

What is the difference between the Prokaryote cell and a Eukaryote cell?

Answer 21

Procayote are small, not bound organelles, has some genetic material

Eukaryote can be 10-50 times bigger
Compartments allow for greater size
arganelles have various jobs

Question 22

What is the difference between plants and animal cells?

Answer 22

Plants have a cell wall, not a plasma membrane
Power for plants is found in the chloroplast not the mitochondria
Plants have a vacuole - for storing

Question 23

Define glycolipids

Answer 23

Lipids that contain a carbohydrate group

Question 24

What is the neucleus enclosed in?

Answer 24

Nuclear envelope

Question 25

What is contained within the nucleolus?

Answer 25

the neucleus

Question 26

What is the main purpose of the ribosomes?

Answer 26

Produce proteins

Question 27

What are the components of the endomembrane system?

Answer 27

``` golgi apparatus rough endoplasmic reticulum smooth endoplasmic reticulum Ribosmes lysosomes plasma membrane ```

Question 28

define lumen

Answer 28

interior of a sac

Question 29

What are nuclear pores?

Answer 29

Openings in the nuclear envelope | as well a connection site for the nucleus and cytosol

Question 30

When proteins are being synthesized by a ribosome where are the three destinations

Answer 30

exported from the cell to the cell membrane -> plasma membrane lysosomes

Question 31

Describe the secretory pathway hypothesis for a protein starting at a ribosome to ejection from the cell

Answer 31

The ribosome attaches to the RER -> proteins enters the lumen of the RER while being synthesised by the ribosome Protein exits ER -> cis face of Golgi apparatus Golgi - folds and finishes the protein packages it up and ships out to plasm membrane

Question 32

What crosses the nuclear envelope?

Answer 32

mRNA out | proteins in

Question 33

What are the 5 steps to the signaling hypothesis

Answer 33

1 - Ribosome makes Protein into the Er with a signal sequence on it - PO 2 - Sequence binds to signal recognition particle (SRP) a complex of RNA & Protein 3 - Ribosome + signal sequence + SRP attaches to receptor in ER Membrane (acts as a key) => unlocks it 4 - once unlocked releases SRP 5 - signal sequence removed & protein synthesis complete

Question 34

How does on know the synthesis of a mambane protein differs from one that will be exported?

Answer 34

it would be directly inserted into the membrane as it is being synthesized instead of fee floating in the lumen

Question 35

When proteins enter the ER what is added?

Answer 35

glycosylation adds carbohydrate groups to proteins

Question 36

what side of the Golgi apparatus is facing the RER

Answer 36

-cis

Question 37

Which side of the Golgi apparatus faces away from the RER?

Answer 37

trans face

Question 38

define endocytosis

Answer 38

general term for pinching off of the plasma membrane that results in the uptake of material from outside of the cell

Question 39

Define exocytosis

Answer 39

secretion of intracellular molecules contained within membrane-bound vesicles, to the outside of the cell by fusion of the vesicles to the plasm membrane contrasing endocytosis

Question 40

Every protein that comes out of the Golgi has a molecular tag with a destination - Where are those three destinations?

Answer 40

Endoplasmic Reticulum Plasma membrane lysosomes

Question 41

As a protein leaves the golgi and has no sequence with a PO - where does it go?

Answer 41

No where - cytoplasm