Quiz 2

Question 1

what are the three principles of the cell theory

Answer 1

1. all organisms are composed of one or more cells
2. the cell is the basic structural and functional unit of all living organisms
3. cells arise only from the division of pre-existing cells

Question 2

What are nuclear localization signals

Answer 2

short proteins that mediate the transport of proteins from the cytoplasm to within the nucelus

Question 3

what proteins need to go in the nucleus

Answer 3

• transcription factors
• histones
• cell cycle regulators
• DNA repair molecules

Question 4

what are lamins and what do they do

Answer 4

they are a network of protein filaments
they line and reinforce the inner surface of the nuclear envelope in animal cells

Question 5

Does the eukaryotic nucleus contain more DNA than the prokaryotic nucleoid

Answer 5

yes. much more

Question 6

what is endosymbiosis

Answer 6

the absorption of one layer of phospholipids by another

Question 7

What is a nuclear pore complex

Answer 7

-large octagonally symmetrical, cylindrical structure formed of many types of proteins (nucleoporins)
- largest protein complex in the cell
- exchanges components (proteins) from the cytoplasm to the cell and prevents materials not meant to cross the nuclear membrane

Question 8

characteristics of eukaryotic ribosomes

Answer 8

• either free in the cytosol or attached to membranes
• translate mRNA into polypeptides (tRNA)
• larger than most (contain 4 types of rRNA molecules and more than 80 proteins.

Question 9

what happens in the lumen (rough endoplasmic reticulum)

Answer 9

addition of carbohydrate groups to eukaryotic ribosomes to produce glycoproteins (little balls on the rough ER)

Question 10

What is the golgi complex responsible for

Answer 10

package and worth the proteins for delivery to their final destinations
size of the complex varies with cell type and cell function

Question 11

what are the 4 steps to protein synthesis and modification

Answer 11

1. mRNA binds to ribosome
2. amino acid chain built within the lumen (space inside cisternae)
3. chaperones help fold the polypeptide into a protein (high concentration with lumen)
4. mods

Question 12

what are the function of the smooth ER

Answer 12

1. synthesis of lipids
2. convert drugs, poison and toxic by-products of cellular metabolism into substances that can be tolerated or more easily removed from the body
3. metabolizes carbohydrates

Question 13

what are cisternae

Answer 13

flattened sacs

Question 14

where does cellular respiration occur

Answer 14

mitochondria

Question 15

what happens in cellular respiration

Answer 15

energy rich molecules (sugars, fats and fuels) are broken down to water and carbon dioxide by mitochondrial reactions, with the release of energy
- most of the energy is captured by ATP

Question 16

what is exocytosis

Answer 16

hormones going out

Question 17

what is ATP

Answer 17

energy currency of the cell

Question 18

what are the three major types of structural elements in animal cells

Answer 18

• microtubules (assembled from dimers of alpha and beta-tubulinproteins)
• intermediate filaments (eight protein chains wind together to form each subunit, shown as a green cylinder
• microfilaments (assembled from two linear polymers of actin proteins wound around each other into a helical spiral

Question 19

function of a microtubule

Answer 19

1. shape, movement (dyneins, kinesis), cell division
2. intracellular transport + signalling

Question 20

function of an intermediate filament

Answer 20

1. cellular stability, organisation
2. regulate cell signalling

Question 21

function of a microfilament

Answer 21

1. movement-muscle contractions
2. intercellular junction: anchors cells to one another

Question 22

the motor proteins walking along microfilaments versus microtubules

Answer 22

microfilaments: myosins
microtubules: dyneins and kinesins( walk by alternately attaching and releasing its feet)

Question 23

what are the three plastids within the plant cell

Answer 23

• chloroplasts : lens or disc shaped surrounded by smooth outer boundary membrane and inner boundary membrane that lies just outside the outer membrane
• amyloplasts : colorless plastids that store starch. occur in great numbers in the roots or tubers
• chromoplasts: contain red and yellow pigments and are responsible for the colours of ripening fruits or autumn leaves.

Question 24

what do all plastids have (p)

Answer 24

DNA genomes, molecular machinery for gene expression and the synthesis of proteins on ribosomes

Question 25

what are central vacuoles (p)

Answer 25

- large vesicles identified as distinct organelles of plant cells because they perform specialized functions unique to plants. - they regulate H2O levels within the cell - occupy 90% of space - pressure in the central vacuole supports the cells (turgor pressure) - divers roles in storage, strudel support and cell growth

Question 26

what membrane surrounds the central vacuole and what does it do (p)

Answer 26

tonoplast. - contains transport proteins that move substances into and out the central vacuole - store salts, organic acids, sugars, storage proteins, pigments, and sometimes waste products

Question 27

where do the pigments concentrated in the vacuoles show up

Answer 27

the colours of flowers

Question 28

characteristics of the cell walls (p)

Answer 28

- consist of cellulose fibres, giving tensile strength to the walls - perforated by minute channels (plasmodesmata (between 1000 and 100 000)) plasmodesmata allow ions and small molecules to move directly form one cell to another through the connecting cytosol without having to penetrate the plasma membrane or cell walls

Question 29

what are cell adhesion molecules (a)

Answer 29

glycoproteins embedded in the plasma membrane cancer cells typically lose these adhesions allowing them to break loose of their original locations and migrate to new locations

Question 30

three types of adhesions (a)

Answer 30

1. anchoring junctions (form button-like spot, or belts , that run entirely around the cell, "welding" adjacent cells togethers 2. tight junctions: seal the spaces between cells in the cell layers that cover internal organs and the outer surface of the body or tat line internal cavities and ducts (ex: stop stomach from leaking into surrounding tissues) 3. gab junctions: open direct channels that allow ions and small molecules to pass directly from one cell to another

Question 31

glucose isomer with OH group pointing below the plane of the ring is

Answer 31

alpha

Question 32

glucose isomer with OH group pointing above the plane of the ring is

Answer 32

beta

Question 33

types of monosaccharides

Answer 33

glucose, fructose galactose 1:2:1

Question 34

isomers that are mirror images of each other like the two forms of glyceraldehyde are called:

Answer 34

enantiomers = stereoisomers (they can be left or right handed)

Question 35

two molecules with the same chemical formula but atoms that are arranged in different ways are called:

Answer 35

structural isomers

Question 36

what two positions can be taken by the OH group

Answer 36

left (L) or right(D) side of the carbon chain

Question 37

How are disacharrides typically assembled

Answer 37

from two monosaccharides linked by a dehydration synthesis reaction these types of bonds are known as glycosidic bonds

Question 38

what is the dehydration synthesis reaction that assembles polysaccharides from monosaccharide an example of

Answer 38

polymerization

Question 39

what are the most common polysaccharides assembled from

Answer 39

starch, glycogen, cellulose, assembled from glucose units

Question 40

are polysaccharides always linear and unbranched?

Answer 40

no they may have branches in which side chains are attached to the main chain

Question 41

what are the three categories of lipids

Answer 41

fats, phospholipids and steroids

Question 42

what is the structural backbone of all lipids derived from

Answer 42

one of two hydrocarbon molecules: isoprene and fatty acids

Question 43

what gives the fatty acid its acidic properties

Answer 43

the carboxyl group

Question 44

what happens when the chain of fatty acids increases

Answer 44

they become less water soluble

Question 45

where can you find phosphate containing lipids

Answer 45

cell membranes: ER, Golgi, vesicle