WEEK 4 Cell structure and function Lecture 4a

Question 1

What are the three main techniques used to study cells?

Answer 1

1. Microscopy
2. Cell fractionation (dissection)
3. Biochemical and molecular analysis

Question 2

Types of microscopy

Answer 2

-Light microscope
-Electron microscope
*scanning electron microscope
*transmission electron icroscope

Question 3

What are the three important parameters in microscopy

Answer 3

Magnification -the ratio of an object image to its real size
resolution-is a measure of the clarity of the image, the minimum distance two points can be separated and still be distinguished as
Contrast-the difference between light and dark areas of an object

Question 4

Cell fractionation

Answer 4

takes cells apart and separates the major organelles from one another while still preserving the functions of each component
-uses ultracentrifuge

Question 5

Prokaryotes and eukaryotes both have?

Answer 5

Chromosomes
DNA/RNA
Ribosomes
membrane
cytoplasm

Question 6

RER

Answer 6

associated with ribosomes, makes secretory and membrane protein

Question 7

SER

Answer 7

makes lipids

Question 8

cytoskeleton

Answer 8

cell shape and structure

Question 9

Lysosome

Answer 9

Digestive compartment

Question 10

Peroxisomes

Answer 10

metabolize waste

Question 11

ribsomes

Answer 11

make proteins

Question 11

Nucleus

Answer 11

Information central

Question 12

Golgi apparatus

Answer 12

modifies proteins

Question 13

plasma membrane

Answer 13

structure

Question 14

mitochondria

Answer 14

produce energy

Question 15

What are the two organelles involved in the genetic control of the cell

Answer 15

nucleus- houses most of the cell’s DNA
ribosomes-uses information from the DNA to make proteins

Question 16

Nuclear membrane

Answer 16

double memrane separating the nucleus from the cytoplasm

Question 17

How does the nucleus regulate entry and exit?

Answer 17

The nuclear envelope is lined with pores of protein structures called pore complex which regulates
the entry and exit of certain large macromolecules and particles

Question 18

How is the shape of the nucleus maintained?

Answer 18

nuclear lamina, a netlike array of protein filaments that mechanically support the nuclear envelope

Question 19

Chromosomes

Answer 19

Found in the nucleus, made of chromatin-a complex of proteins and DNA

Question 20

Nucleolus

Answer 20

Condensed region where ribosomes RNA are synthesized

Question 21

What are ribosomes

Answer 21

particles made of ribosomal RNA and protein, its function is to carry out protein synthesis.

Question 22

ribosomes carry out protein synthesis in two locations

Answer 22

-in the cytosol (free ribosomes)
-attached to the outside of the endoplasmic reticulum or the nuclear envelope

Question 23

What is The Endomembrane System

Answer 23

the endomembrane system regulates protein traffic and performs metabolic functions of the cell

Question 24

What are the components of the endomembrane system

Answer 24

• Nuclear envelope
• Endoplasmic reticulum
• Golgi apparatus
• Lysosome
• Vacuole and vesicles
• Plasma membrane

Question 25

Describe the structure and function of RER

Answer 25

Ribosomes studding its outer surface giving it a rough appearance> responsible for:
-Bound ribosomes secrete glycoproteins
-Distributes transport vesicles, proteins surrounded by membranes
Its a membrane factory for the cell: it grows by adding phospholipids and membrane proteins to its own membrane-This expands the ER which is transferred in the form of
transport vesicles to other components of the
endomembrane system.

Question 26

Describe function of SER

Answer 26

-Synthesizes lipids: including oils, phospholipids, and steroids
-metabolizes carbohydrates
-detoxifies harmful substances
-stores calcium

Question 27

Golgi apparatus structure and function

Answer 27

_consists of flattened membrane sacs called cisternae
-Modifies proteins of ER during their transit from cis region to trans region of the golgi
-manufactures certain macromolecules
-sorts and packages molecules into vesicles for transportation

Question 28

Lysosome

Answer 28

-Lysosomes are organelles that contain hydrolase enzymes that break down waste material and cellular debris
-Lysosomes fuse with vacuoles and dispense their enzyme into the vacuoles, digesting their contents

Question 29

What is phagocytosis

Answer 29

When cells engulf other cells, forming vacuoles

Question 30

What is autophagy

Answer 30

The process by which hydrolytic enzymes of lysosomes recycle the cells own organic material

Question 31

Vacuoles??

Answer 31

• Vacuoles carry out hydrolysis and are similar to lysosomes but they also carry out
  other functions as well
• Vacuoles are large vesicles derived from the ER and Golgi apparatus; it is an
  integral part of a cell’s endomembrane system
• Vacuoles are single-membrane organelles that are essentially part of the outside
  that is located within the cell
• Vacuoles performs various functions in different kinds of cells:
  -Food vacuoles in phagocytosis
  -contractile vacuoles in protists that pumps excess water out of the cell
  -central vacuoles in plants contains sap repository of inorganic ions and
  growth
• Many organisms will use vacuoles as storage areas
• Vesicles are much smaller than vacuoles and function in transporting materials
  both within and to the outside of the cell