BIOL 150 Test 2

Question 1

What are the three components of the cell theory?

Answer 1

1. Cells are the smallest living things
2. Cells arise only by the division of a previously existing cell
3. All living organisms are composed of one or more cells

Question 2

Explain why cell size is limited

Answer 2

Cell size is limited because it has to diffuse substances into and out of the cell. The rate of diffusion is affected by (1) SURFACE AREA AVAILABLE FOR DIFFUSION (2) temperature, (3) concentration gradient of diffusing substance, and (4) the distance over which diffusion must occur (thickness of membrane). AS THE SIZE OF A CELL INCREASES, ITS VOLUME INCREASES MUCH MORE RAPIDLY THAN ITS SURFACE AREA, THEREFORE THE LENGTH OF TIME FOR DIFFUSION FROM THE OUTSIDE MEMBRANE TO THE INTERIOR OF THE CELL INCREASES AS WELL.

Question 3

Describe the change in surface area to volume ratio as cells increase in size

Answer 3

For a spherical cell, the surface area is proportional to the square of the radius while the volume is proportional to the cube of the radius.

Question 4

List the four structural similarities found in cells

Answer 4

1. A nucleoid or nucleus where genetic material is located
2. Cytoplasm
3. Ribosomes to synthesize
4. A plasma membrane

Question 5

Compare the characteristics of eukaryotic and prokaryotic cells as shown in the table

Answer 5

Prokaryotes - have DNA in nucleoid region, are smaller in size, usually single-celled, may not need oxygen, and has no membrane-bound organelles
Eukaryotes - have DNA inside membrane-bound nucleus, are larger in size, often multicellular, usually need oxygen to exist, have membrane-bound organelles

Question 6

Cell wall and cell membrane differences between bacterial and archaeal cell types

Answer 6

Bacterial Cells -
cell wall composed of peptidoglycan (carbohydrate matrix cross-linked with short polypeptide units)
cell walls protect the cell, maintain shape, and prevent excessive uptake/loss of water
Archaeal Cells -
cell wall made of polysaccharides, proteins, and sometimes inorganic components
membrane lipids include saturated hydrocarbons covalently attached to glycerol at both ends (forms a monolayer membrane)
membranes confer greater thermal stability (but cannot alter degree of saturation, therefore limiting response to changing environmental temperatures)

Question 7

Plasma Membrane

Answer 7

Regulates what passes into and out of the cell; cell-to-cell recognition; connection and adhesion; cell communication

Question 8

Nucleus

Answer 8

Instructions for protein synthesis and cell reproduction; contains genetic information

Question 9

Chromosomes

Answer 9

Contain hereditary information used to direct synthesis of proteins

Question 10

Nucleolus

Answer 10

Synthesis of rRNA and ribosome assembly

Question 11

Ribosomes

Answer 11

Sites of protein synthesis

Question 12

Endoplasmic Reticulum (ER)

Answer 12

Intracellular compartment forms transport vesicles; participates in lipid synthesis and synthesis of membrane or secreted proteins

Question 13

Golgi Apparatus

Answer 13

Packages proteins for export from cell; forms secretory vesicles

Question 14

Lysosomes

Answer 14

Digest worn-out organelles and cell debris; digest material taken up by endocytosis

Question 15

Microbodies

Answer 15

Isolate particular chemical activities form rest of cell

Question 16

Mitochondria

Answer 16

“Power plants” of the cell; sites of oxidative metabolism

Question 17

Chloroplasts

Answer 17

Sites of photosynthesis

Question 18

Cytoskeleton

Answer 18

Structural support; cell movement; movement of vesicles within cells

Question 19

Flagella (cilia)

Answer 19

Motility or moving fluids over surfaces

Question 20

Cell Wall

Answer 20

Protection; support

Question 21

Cell walls are present in

Answer 21

prokaryotes and plants

Question 22

Cell membranes are present in

Answer 22

prokaryotes, animals, and plants

Question 23

Flagella/cilia are present in

Answer 23

flagella may be present in prokaryotes, both may be present in animals (9 + 2
structure), and both are absent in plants except in sperm of a
few species (9 + 2 structure)

Question 24

Endoplasmic reticulum is present in

Answer 24

usually present in plants and animals

Question 25

Ribosomes are present in

Answer 25

plants and animals

Question 26

Microtubules are present in

Answer 26

plants and animals

Question 27

Centrioles are present in

Answer 27

animals

Question 28

Golgi Apparatus is present in

Answer 28

plants and animals

Question 29

Nucleus are present in

Answer 29

plants and animals

Question 30

Mitochondria are present in

Answer 30

plants and animals

Question 31

Chloroplasts are present in

Answer 31

plants

Question 32

Chromosomes are present in

Answer 32

prokaryotes as a single circle of DNA; animals as multiple DNA-protein complex; plants as multiple DNA-protein complex

Question 33

Lysosomes are present in

Answer 33

Usually present in animals, and present in plants

Question 34

Vacuoles are present in

Answer 34

absent or small in animals; usually a large single vacuole in plants

Question 35

Explain how a protein is transported through the endomembrane system

Answer 35

Proteins are manufactured in the rough and smooth ER membranes and then transported to the Golgi apparatus, being modified as they pass through it. The most common alteration performed by the Golgi apparatus is adding short sugar chains, forming glycoproteins (existing glycoproteins can also be altered by adding or modifying sugars). These are then packaged into vesicles that pinch off from the trans face of the Golgi. These vesicles diffuse to other locations in the cell, distributing the newly synthesized molecules to their appropriate destinations.

Question 36

Describe the probable origin of mitochondria and chloroplasts

Answer 36

Mitochondria and chloroplasts arose by endosymbiosis. This thoery proposes that these organelles and some other eukaryotic cells evolved from a symbiosis between different species of prokaryotes that were each free-living. I.e., one cell, a prokaryote, was engulfed by and became part of another cell.

Question 38

As a cell increases in size, the surface area increase _______ than the volume.

Answer 38

less

Question 39

The surface area of a cell increases proportionally to the radius ______

Answer 39

squared

Question 40

The volume of a cell increases proportionally to the radius _____

Answer 40

cubed

Question 41

Protein processing pathway

Answer 41

1) Vesicle containing proteins buds from the rough endoplasmic reticulum, diffuses through the cell, and fuses to the cis face of the Golgi apparatus. 2) The proteins are modified and packaged into vesicles for transport. 3) The vesicle may travel to the plasma membrane, releasing its contents to the extracellular environment.

Question 42

Know parts of endomembrane system mitochondria chloroplasts phospholipid

Answer 42

kk

Question 43

The evolutionary process that created chloroplasts and mitochondria is

Answer 43

endosymbiosis

Question 44

Microfilaments such as actin, microtubules, and the intermediate filaments form the cell-supporting structure called the

Answer 44

cytoskeleton

Question 45

Integrins are glycoproteins that help link the cytoskeleton and the

Answer 45

extracellular matrix

Question 46

Organelles that breakdown hydrogen peroxide into water and oxygen are

Answer 46

peroxisomes

Question 47

A circular molecule of DNA devoid of any histone proteins describes the chromosome of a (an)

Answer 47

bacteria

Question 48

Prokaryotic cell movement is attributed to

Answer 48

flagella

Question 49

The eukaryotic organelle that is directly involved in the transport of proteins synthesized on the surface of the rough ER is called the

Answer 49

golgi apparatus

Question 50

In eukaryotes, mitochondria are the organelles primarily involved in

Answer 50

energy release/capture

Question 51

Plant cells often have a large membrane-bound sac that is used for storing water and other substances called a

Answer 51

central vacuole

Question 52

Mitochondria and chloroplasts are the other organelles besides the nucleus that contain

Answer 52

DNA

Question 53

You stain a cell with a dye that reacts with an enzyme found in the lysosome. You would also expect to see this dye in the

Answer 53

endoplasmic reticulum

Question 54

Sulfolobus are archaea that are commonly found in geothermal environments, with an optimum growth temperature of about 80°C. What feature allows archaea to thrive at such temperatures?

Answer 54

Archaeal membranes contain special lipids

Question 55

A protein that is destined to reach the plasma membrane is making its way through the Golgi. At that moment, a drug was added to cells, blocking trafficking at the trans face of the Golgi. As a result, what would happen to the protein?

Answer 55

The protein would be stuck in the Golgi.

Question 56

Based on the function of mitochondria, what substance is able to pass through the outer membrane of the mitochondria easily?

Answer 56

oxygen

Question 57

Individuals that are heavy smokers may eventually have trouble clearing the mucous from their lungs because the structures that move fluid along the epithelial lining of the lung become damaged over time. What are these structures called?

Answer 57

cilia

Question 58

Streptomycin is an antibiotic that interferes with the function of the 30S subunit of the prokaryotic ribosome. What is the consequence of treating a bacteria with streptomycin?

Answer 58

impaired protein synthesis

Question 59

A dish of cells is treated with centrinone, a centriole inhibitor. These cells would no longer be able to _________.

Answer 59

divide

Question 60

As ATP moves from the matrix of the mitochondrion to the cytoplasm of a cell, how many membranes will it pass?

Answer 60

2

Question 61

How do membranes form spontaneously?

Answer 61

The hydrophobic fatty acid tails on phospholipids are repelled by water.

Question 62

Glucose is taken up by red blood cells by binding to a specific pocket in a membrane protein which then allows it to cross the membrane and move down its concentration gradient. What would be the best definition of this process?

Answer 62

Facilitated diffusion using a transporter

Question 63

Exocytosis

Answer 63

Exocytosis is a process that occurs when a cell moves large materials from inside the cell to the outside of the cell using small spheres of membrane called vesicles. This process is a form of active transport, meaning it uses energy.

Question 64

The hormone insulin is a protein produced in the pancreas and then secreted into the blood stream after a meal to increase glucose uptake by tissues. What cellular process is used to secrete insulin from the pancreas?

Answer 64

exocytosis

Question 65

What describes the movement of substances down their concentration gradients?

Answer 65

Diffusion

Question 66

Osmosis is the diffusion of water across a membrane in response to the concentration of one or more of the ______.

Answer 66

solutes

Question 67

In a single pump cycle where sodium and potassium are exchanged and ATP is used, the following is expected

Answer 67

3 sodium ions leave and 2 potassium ions enter

Question 68

A type of molecule movement of that is specific and passive and becomes saturated if all of the protein carriers are in use

Answer 68

facilitated diffusion

Question 69

Receptor-mediator endocytosis

Answer 69

Receptor-mediated endocytosis, also called clathrin-mediated endocytosis, is a process by which cells absorb metabolites, hormones, proteins – and in some cases viruses – by the inward budding of the plasma membrane.