lecture #6 eukaryotic cells

Question 1

what are the 2 types of organelles

Answer 1

• membranous organelles: surrounded by a membrane
  ex: plasma membrane, cytoplasme, nucleus, ER, golgi, vesicles, lysosomes, peroxisome, mitochondria, chloroplasts, vacuoles

non membranous organelles
no membrane protection

ex: nucleolus, ribosomes, cutoskeleton, centrosome, cilia, flagella, cell junctions, cell wall, extracellular matrix

Question 2

what is the function of the plasma membrane

why is it useful to seperate external and internal enviroment

Answer 2

• boundary between cell contents and surroundings
• regulate movement in and our of cell
• interior of cell environment critically balanced

Question 3

what is the plasma membrane composed of

Answer 3

1- phospholipid molecules
2- protein molecules
3. (cholesteral)

Question 4

what is cytoplasm

Answer 4

region between nucleus and plasma membrane

Question 5

what is cytosol

Answer 5

fluid substance within the membrane that contains the organelle (in cytoplasm)

Question 6

give the characteristics of the nucleus

Answer 6

• wrapped in double membrane
• pores to permit exchange of materiels between nucleus and cytoplasm

Question 7

what important structure does the nucleus contain

Answer 7

nucleolus : makes ribosomes

Question 8

functions of nucleus

Answer 8

• control center of the cell
• contains DNA 2m long

Question 9

what are the 2 types of DNA

Answer 9

chromatin: loosely arranged DNA and protein

chromosomes: tightly packed DNA and proteins (histones)

Question 10

What is the endoplastic reticulum

Answer 10

• the ER membrane is continuous with the nuclear envelope
• 2 kinds:
  1) rough with ribosomes
  2) smooth (no ribosomes)

Question 11

what is the function of rough ER

Answer 11

1 - synthesis and transports protein
a) secretory proteins that will exit the cell
b) proteins destined for other organelles

2 - modification of proteins
- folds into 3D conformation
- enzymes

Question 12

what is the function of smooth ER

Answer 12

1- synthesis and transports lipids
2- metabolises
3- storage of calcium
4- detoxifies

Question 13

what is the difference between smooth and rough ER

Answer 13

rough = with ribosomes
smooth = without ribosomes

Question 14

what is the golgi apparatus

Answer 14

1- chemical modification
2- packaging and exporting of various molecules
3- synthesizes caarbohydrates

Question 15

what are the vesicles

Answer 15

• hollow spherical organelles

function: store and transport chemicals throughout the cell

2 types secreted by ER and golgi:
1. Transport (ER)
2. Secretory (golgi)

Question 16

what are lysosomes

Answer 16

vesicles (produced by golgi) that contain specific enzymes
function: destroy specified substances

Question 17

what are the 2 different types of lysosomes

Answer 17

1- phagocytosis : digest materiel taken from outside of cell

2- Autophagy : destroys organelles taken from inside the cell (itself)

Question 18

what is the theory surronding the mitochondria

Answer 18

thought to derive from bacteria-like endosymbionts, integrated into the cell millions of years ago

Question 19

what are peroxisomes

Answer 19

Fatty acid metabolism
- Detoxify alcohol & other harmful
compounds (in liver)
Peroxisomes
* Peroxisomes can self-replicate!

Question 20

what do lysomal enzymes need to work?

Answer 20

acidic environment, if they break open, not as effective because are in cytosol, which is not very acidic