W1-lecture 2: Structure and function

Question 1

What are the properties of all cells?

Answer 1

Metabolism Growth Evolution

Question 2

What are the properties of some cells?

Answer 2

Differentiation Communication Genetic exchange Motility

Question 3

T or F : There is an advantage of being small because your surface-to-volume ratio is higher.

Answer 3

T

Question 4

What are the building units of the cytoplasmic membrane

Answer 4

constructed from either phosphoglycerol diethers, which have C20 side chains (called a phytanyl group) or diphosphoglycerol tetraethers (C40 side chains, called a biphytanyl group)

Question 5

What stabilize the membrane in : animal cells, fungi and plant cells (and protozoans)

Answer 5

Animal : Cholesterol Fungi : Ergosterol Plan cells and some protozoans: Stigmaterol

Question 6

T or F : In bacteria and archaea, sterols are almost always absent.

Answer 6

T, the membrane is stabilize by hopanoids in bacteria

Question 7

What stabilize the membrane in bacteria

Answer 7

hopanoids (sterol life structure)

Question 8

in procryotes, the ribosomes subunits are : ___S and ___S

Answer 8

30 + 50 = 70S

Question 9

in eucaryotes, the ribosomes subunits are : ___S and ___S

Answer 9

40 + 60 = 80S

Question 10

What is the difference between a cell wall and a membrane?

Answer 10

The main difference between cell wall and cell membrane is, cell membrane is present in all cells but cell wall is only present in plants, bacteria, fungi and algae. It is not present in the Protozoa and animal cell. Cell wall covers the cell membrane, which is a partially permeable membrane.

Question 11

What are the differences between the layer of the archea and the bacteria?

Answer 11

1- the hydrophobic lipid in archaea is not a fatty acid it is repeated units of isoprene 2- the link between the hydrophobic part anf the glycerol is an ether in the case of archaea instead of an ester 3- Can form a bi-layer or a mono-layer in the case of archaea

Question 12

What is the name of the major phospholipid found in bacteria?

Answer 12

Phophatidylethanolamine

Question 13

What type of linkage link the phosphoglycerol and the hydrophobic portion (phyntanyl)

Answer 13

ether linkage as opposed to a ester linkage in the case of bacteria and eukaryotes

Question 14

What are the three functions of the membrane?

Answer 14

1- Permeability barrier 2- Protein anchor 3- Energy conservation (for archae and bacteria)

Question 15

What is composed the lipid portion in the bi-layer of archaea?

Answer 15

Isoprene units (5 carbons)

Question 16

How many carbons is there in a phyntanyl group?

Answer 16

20Carbons

Question 17

What are the three types of phosphoglycerol that you can find in the membrane of archaea?

Answer 17

1- Phosphoglycerol diether 2-Diglycerol tetraethers 3-Crenarchaeol

Question 18

T or F : protozoan’s cell wall is made of cellulose.

Answer 18

F, the protozoans don’t have a cell wall.

Question 19

T or F : animal’s cell wall is made of polysaccharides

Answer 19

False, they don’t have a cell wall (extralayer over the cell membrane)

Question 20

What is made the cell wall of :
1- Plants, algea :
2- Fungi :

Answer 20

1- Plants, algea : cellulose (polymers of glucose)
2- Fungi : cellulose or chitin (polymers of n-acetylglucosamine).

Question 21

What is the universal hallmark of the eukaryotic cells?

Answer 21

presence of a enclosed nucleus

Question 22

What is the heterochromatin?

Answer 22

Densely packed, low level of transcription way of compacting compacting the nucleosomes (4 histones and the DNA strand around it)

Question 23

What is the euchromatin?

Answer 23

Loosely packed, actively transcribed way of compacting the nucleosomes (4 histones and the DNA strand around it)

Question 24

What is the name of the ribosome rich part of the nucleus?

Answer 24

nucleolus

Question 25

What is the name of the organelle that is a network of membranes continuous with the nuclear membrane?

Answer 25

the endoplasmic reticulum

Question 26

What is the function of the golgi body?

Answer 26

The Golgi body is a set of membrane compartments involved in further processing of proteins and their distribution. Proteins are packaged in vesicles and transported to where they are required.

Question 27

What is the name of the invagination of the membrane in the mitochondria?

Answer 27

Cristea.

Question 28

What is the equivalent of the mitochondria in phototrophic eukaryotes

Answer 28

The chloroplast.

Question 29

Where are contains the enzymes and pigments that harvest light energy and the membrane-bound ATPases that uses this energy to producde ATP

Answer 29

Thylakoids inside the chloroplast

Question 30

Where is the site of the calvin cylce, the assimilation of CO2 and biosynthesis in the phototrophic eukaryotes (be precise)

Answer 30

The stroma of the choloroplasts.

Question 31

Where are found the proteins that harvest light energy in the photosynthetic prokaryotes?

Answer 31

They are found in the cytoplasmic membrane.

Question 32

T or F : the choloplast and the mitochondria came from the engulfing of archaea a long time ago. (endosymbiotic theory)

Answer 32

False, it came from the engulfing of the bacteria.

Question 33

Name three structure of the cytoskeleton in eukaryotes

Answer 33

1. microtubules 2. actin filament 3. intermidiate filaments

Question 34

What are the single proteins that make the microtubules?

Answer 34

alpha and beta tubulin

Question 35

What are the single proteins that make the actin filaments?

Answer 35

actin

Question 36

What are the single proteins that make the intermidiate filament?

Answer 36

keratin, desmin and vimentin

Question 37

name the cytoskeleton parts

Question 38

What is the role of the microtubules?

Answer 38

1. Serves has highway for the transport of organelles 2. Maintain the cell shape by resisting compression (push) 3. Assist formation of cell plate during plant cell division 4. Moves cells via flagella and cillia.

Question 39

what is the name of the proteins that makes the link between the microtubules and the transport vesicles

Answer 39

kinesin and dynein.

Question 40

What is the function of the actin filaments

Answer 40

1. Maintain cell shape by resisting tension 2. move cells via muscle contraction or cell crawling 3. Divide cells into two 4. move organeles and cytoplasm in plants fungi and animals

Question 41

What are the functions of the intermidiates filaments?

Answer 41

1. Maintain the cell shape by resisting the tension 2. Anchor nucleus and some organelles

Question 42

How many microtubules is contained in a flagella or cilia?

Answer 42

9 pairs around a central pair of microtubules. 20 microtubules in total.

Question 43

What is the protein that uses ATP and drives the motility in the flagella and cilia.

Answer 43

Dynein