Unit 2 Quiz/HW

Question 1

Viruses are no living particles with a genome made of a DNA or ___, surrounded by a shell (capsid) made of ___

Answer 1

RNA and protein

Question 2

Viruses are unable to reproduce without which of the following?

Answer 2

A host cell

Question 3

Most viruses have a capsid that is ___ or ___ in terms of its basic structure and symmetry

Answer 3

Icosahedral and helical

Question 4

Viral genomes may be composed of ___ or ___ and may be ___-strangded or ___-stranded

Answer 4

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)

Single and double

Question 5

What describes a virus

Answer 5

A small biological particle comprised of Nucleic acid enclosed in a protein coat

Question 6

How do viruses replicate

Answer 6

Host cells transcriptions and translation systems are used to replicate the genome and create capsize proteins

Question 7

What of the following are reasons why classifying viruses by the disease they cause can be impractical?

Answer 7

Some viruses do not appear to cause any disease
Some viruses can cause different diseases in different contexts
The same disease can be caused by many different viruses

Question 8

In the Baltimore classification of viruses, there are ___ groups of viruses and every known virus can be placed in only one such group bases on the way it ___ its genome.

Answer 8

7 and replicates

Question 9

In order to study viruses in the environment, scientists isolate nucleic acids from an environmental sample, sequence them, and use computers to assemble genomes and compare them to known sequences in databases. This approach is known as

Answer 9

Metagenomics

Question 10

Why is it difficult to classify influenza viruses based on their host?

Answer 10

Because there are 4 types of influenza that can infect many different (humans, birds, pigs, dogs, cats)

Question 11

Bacteria-infecting viruses are also known as

Answer 11

Bacteriophage

Question 12

The classification of viruses based on genome replication is known as the ___ classification after the scientist that first proposed it.

Answer 12

Baltimore

Question 13

Rank the following cells and particles in order according to size, with the smallest at the top and largest at the bottom.

Answer 13

Protein
T2 bacteriophage
Influenza virus
E. Coli bacterium
Eukaryotic cell

Question 14

What is a characteristic of the lyric cycle

Answer 14

A large number of phages is released at a time

Question 15

Viruses that contain ___ as their genetic material are often assigned to species group; the same is not true of viruses with ___ as their genetic material

Answer 15

DNA and RNA

Question 16

___ involves isolating DNA from an environmental sample, sequencing it, and compared it to known sequences in DNA databases

Answer 16

Metagenomics

Question 17

What viruses uses the cellular machinery of a bacteria for its own replication

Answer 17

Bacteriophage

Question 18

___ is a condition characterized by viruses freely circulating in the blood or lymph

Answer 18

Viermia

Question 19

Regarding bacteriophage, during which type of cycle does the phage enter a latent phase, allowing it to be replicated with the host cell?

Answer 19

Lysogenic

Question 20

What are the conventional systematic groups that are also used to classify viruses

Answer 20

Family, genus, and order

Question 21

What are the two main ways in which a virus can spread to infect secondary sites in the human body?

Answer 21

In blood or lymph
Via neurological tissue

Question 22

Compared to archaea viruses, bacteriophages are

Answer 22

Less diverse in their morphologies

Question 23

Bacteriophage exhibit two reproductive cycles: the __ cycle, in which the latent phage is replicated with the host cell, and the ___ cycle, in which phage undergo replication within the host cell, eventually causing it to rupture.

Answer 23

Lysogenic
Lytic

Question 24

A ___ viral infection involves the rapid replication of the virus, often at the site of infection, which leads to sudden symptom onset

Answer 24

Acute

Question 25

Bacteriophage contribute DNA to their hosts during the ___ cycle, which may allow phage genes to be expressed with those of the host.

Answer 25

Lysogentic

Question 26

In ___ viral infections, a virus or its genomes can be found in the host for long periods of time: years, decades, and sometimes for the rest of the hosts life

Answer 26

Persistent

Question 27

What is true regarding Archean viruses and bacteriophages

Answer 27

Both can have double-stranded DNA as their genome Archaea viruses are more diverse in their morphologies than bacteriophages

Question 28

What is the effect of the initial acute disease episode after infection with an HSV-1 or HSV-2

Answer 28

Formation of painful blisters at the site of infection

Question 29

An ___ disease is a disease that appears in the population for the first time, or that spreads to a new geographical area

Answer 29

Emerging

Question 30

What are the characteristics of acute viral infections

Answer 30

They result in the sudden symptom onset They involve rapid viral replication They often (no always) establish at the site of infection

Question 31

The disease that causes the development of numerous small cavities in the brain of infected individuals due to death of neurons, producing a spongy appearance, is called

Answer 31

Transmissible spongiform encephalopathy

Question 32

The 3 types of persistent human viral infections based on the amount of virus present and when it is produced

Answer 32

Chronic Slow Latent

Question 33

Infectious proteins that can cause transmissible spongiform encephalopathies are called ___

Answer 33

Prions

Question 34

After the initial acute disease (painful blisters) subsides due to an immune response, where can HSV-1 and HSV-2 be found?

Answer 34

In the nuclei of sensory neurons that innervate the site of infection

Question 35

Transmissible spongiform encephalopathies cause

Answer 35

The development of numerous small cavities in the brain as neurons die

Question 36

After the immune system can no longer control HIV, it starts killing cells expressing the CD4 antigen. Of those cells, the most important types are the ___ cells which coordinate the immune response, and the ___ which engulf pathogenic bacteria

Answer 36

T-helper and macrophages

Question 37

A disease that was prominent in the past, and whose incidence suddenly increases after a period of low incidence, is called a

Answer 37

Re-emerging

Question 38

Which infectious agents are composed solely of RNA

Answer 38

Viroids

Question 39

Cells continually exchange materials and information with their environment. This exchange is crucial

Answer 39

For all the processes occurring in a cell

Question 40

The lipid bilayer that forms the core of all cell membranes is composed primarily of

Answer 40

Phospholipids

Question 41

Which of the following is not one of the four main components of all plasma membranes?

Answer 41

Extracellular matrix

Question 42

What type of microscope can be used to see the two phospholipid layers in a plasma membrane?

Answer 42

Electron

Question 43

Although a eukaryotic cell membrane can contain many different lipids, they can be classified in three groups: glycerol phospholipids, ___, and ___. When answering the question think about the lipids found in membranes, not about all the lipids that an organism makes!

Answer 43

Sphingolipids and sterols

Question 44

In order to survive, grow, and reproduce, a cell must

Answer 44

Exchange materials and info with its environment

Question 45

What makes up the bilayer of every cell membrane?

Answer 45

Phospholipids

Question 46

When phospholipids are placed in water, they spontaneously form a bilayer with which of the following?

Answer 46

The polar heads on the surface and the non polar tails in the interior

Question 47

What are the four main components of all eukaryotic membranes.

Answer 47

Interior protein network Cell surface makers Transmembrane proteins Lipid bilayer

Question 48

What is true about cell membranes

Answer 48

The degree of membrane fluidity caries depending on the composition of the membrane Individual lipids and unanchored proteins are relatively free to move around laterally within the lipid bilayer

Question 49

The lack of double bonds in saturated fats allow them to pack together tightly, and therefore the membrane is ___ fluid. The presence of double bonds in unsaturated fats prevent them from packing together tightly, and therefore the membrane is ___

Answer 49

Less and more

Question 50

three groups of lipids found in eukaryotic cells.

Answer 50

Sphingolipids Glycerol phospholipids Sterols

Question 51

The ER membrane is typically more fluid than the plasma membrane and it contains more curvature. Why?

Answer 51

The ER membrane contains mainly unsaturated phospholipids

Question 52

Cells continually exchange materials and information with their environment. This exchange is crucial ___

Answer 52

For all the process occurring in a cell

Question 53

What ar all functions typically carried out by membrane proteins.

Answer 53

Connect adjacent cells and hold them together Receive external chemical messages Attach the membrane to the cytoskeleton

Question 54

When phospholipids are placed in water, they spontaneously form which of the following?

Answer 54

A bilayer

Question 55

What statement is true of transmembrane domains.

Answer 55

Transmembrane domains are composed of hydrophobic amino acids

Question 56

What are accurate statements concerning membrane fluidity.

Answer 56

Phospholipids are relatively free to move around laterally within the membrane. Unanchored proteins are relatively free to move around laterally within the membrane. The degree of membrane fluidity varies depending on the composition of the membrane.

Question 57

What describes passive transport?

Answer 57

It does not require an expenditure of energy but the cell itself

Question 58

How does lipid composition affect membrane fluidity?

Answer 58

Sterols, such as cholesterol, can either increase or decrease membrane fluidity depending on temperature Saturated fatty acids tend to make the membrane less fluid because they pack together well.

Question 59

Compared to the ER membrane, the plasma membrane contains more

Answer 59

cholesterol sphingomyelin phosphatidylcholine

Question 60

Due to the constant random motion of its atoms and molecules, a substance will exhibit net movement from a region where it has a higher concentration to a region where it has a lower concentration. This net movement is called

Answer 60

Diffusion

Question 61

What are key functions carried out by membrane proteins?

Answer 61

Receive external chemical messages Catalyze specific chemical reactions on the surface of the membrane Transport specific ions and molecules across the membrane Function as cell-surface identity markers

Question 62

Each membrane-spanning region of a transmembrane protein is called a transmembrane

Answer 62

Domain

Question 63

Transport that occurs without a cell expending any of its own energy is called ___ transport

Answer 63

Passive

Question 64

The plasma membrane can best be described as which of the following?

Answer 64

Selective permeable

Question 65

The most abundant molecule in the cytoplasm is the ___ molecule

Answer 65

Water

Question 66

While ___ transport requires the cell to expend some of its own energy, ___ transport does not

Answer 66

Active and passive

Question 67

Carrier proteins that transport 2 different types of molecules or ions may be either ___ or anti porters

Answer 67

Symporters

Question 68

Which is true of the plasma membrane?

Answer 68

It is fluid It is selectively permeable

Question 69

Which are required for the sodium potassium pump in cells to work?

Answer 69

Carrier proteins ATP

Question 70

The cytoplasm contains ions and molecules dissolved in ___

Answer 70

Water

Question 71

Which type of transport proteins use energy from ATP indirectly?

Answer 71

Coupled transport proteins

Question 72

Based on the direction of movement, bulk transport can be divided into two main categories: ___ and ___

Answer 72

Endocytosis and exocytosis

Question 73

Which type of transport proteins use energy from ATP directly?

Answer 73

Protein pumps

Question 74

What are the three main types of endocytosis?

Answer 74

Receptor-mediated endocytosis Pinocytosis Phagocytosis

Question 75

The two main categories of ___ ___ are endocytosis and exocytosis

Answer 75

Bulk and transport

Question 76

The fusion of a secretory vesicle with the plasma membrane in order to discharge the contents of the vesicle is called

Answer 76

Exocytosis

Question 77

Transport that requires a cell to expend some of its own energy, typically from ___, is called ___ transport

Answer 77

ATP and active

Question 78

Phagocytosis is one of the mechanisms of what

Answer 78

Endocytosis

Question 79

The reverse of endocytosis is ___

Answer 79

Exocytosis

Question 80

Which of the following is the branch of chemistry concerned with energy changes?

Answer 80

Thermodynamics

Question 81

The energy that flows through most biological systems on Earth ultimately comes from which source?

Answer 81

The sun

Question 82

___ stored in the chemical bonds of a molecule can be used to make new bonds in a different molecule.

Answer 82

Potential energy/free energy

Question 83

All activities of living organisms involve changes in ___ which is the ability to do work

Answer 83

Energy

Question 84

True or false: Thermodynamics is the study of energy changes in the Universe.

Answer 84

True

Question 85

The energy available to do work in a system is called ___ energy

Answer 85

Free

Question 86

The process of influencing chemical bonds to lower the activation energy of a reaction is called ___

Answer 86

Catalysis

Question 87

All living things require which of the following, in order to carry out chemical reactions and thereby survive?

Answer 87

Energy

Question 88

What molecule is a common energy source for living organisms?

Answer 88

ATP

Question 89

Hydrolysis of which covalent bonds in ATP releases a considerable amount of energy?

Answer 89

Phosphate-phosphate bond

Question 90

All cells use a molecule called ___ to carry and release energy cyclically

Answer 90

ATP

Question 91

steps in the ATP cycle

Answer 91

Synthesis of ATP using energy released from exergonic reactions Hydrolysis of ATP to release energy that can be used to drive endergonic reactions

Question 92

Name the type of energy that is a form of potential energy stored in chemical bonds.

Answer 92

Chemical

Question 93

Is any energy released during ATP hydrolysis and if so, how much?

Answer 93

Yes, a considerable amount of energy is released

Question 94

___ are proteins or RNA molecules that act as catalysts to speed up reactions in living organisms

Answer 94

Enzymes

Question 95

Calls use ___ hydrolysis to drive endergonic reactions.

Answer 95

ATP

Question 96

What is a true statement about enzymes.

Answer 96

They lower the activation energy of a reaction by binding to the substrates.

Question 97

The two main steps in the ATP cycle are the synthesis of ATP from ___ and Pi, and the subsequent hydrolysis of ATP, which releases ___ that drives Endergebnis reactions

Answer 97

ADP and energy

Question 98

True or false: All of the enzymes that a cell has are found in the cells' cytoplasm.

Answer 98

False

Question 99

Certain reactions in cells are endergonic. How do cells make those reactions proceed?

Answer 99

They couple them with ATP hydrolysis

Question 100

True or false: Substances can bind to an enzyme and change its shape, affecting its activity.

Answer 100

True

Question 101

___, or reactants, are molecules that bind to an enzyme at the active site and are converted to products in chemical reactions.

Answer 101

Substrates

Question 102

What are true statements that accurately describe cellular enzymes.

Answer 102

Different enzymes can come together to form complexes. Some cellular enzymes are found inside of cellular organelles. Not all cellular enzymes are located in the cytoplasm

Question 103

What is included in metabolism?

Answer 103

Both the synthesis and breakdown of organic molecules

Question 104

What is true about the regulation of enzyme activity in cells?

Answer 104

Calls can regulate the activity of enzymes by inhibiting or activating them

Question 105

True or false: Biochemical pathways evolved quickly over time.

Answer 105

False

Question 106

What is a substrate?

Answer 106

A reactant molecule that binds to the active site of an enzyme

Question 107

True or false: Each step of a metabolic pathway is catalyzed by a specific enzyme.

Answer 107

True

Question 108

During each step of the metabolic pathway that adds phosphate groups to various sugars, a separate ___ is needed to catalyze the reaction

Answer 108

Enzyme/protein

Question 109

why are metabolic pathways are regulated.

Answer 109

Requlation allows cells to operate efficiently. By regulating metabolic pathways, cells waste less energy. By regulating metabolic pathways, cells conserve raw materials.

Question 110

T or F: When ATP is used in a reaction, the last phosphate is transferred to the substrate.

Answer 110

True

Question 111

T or F: Release of the last phosphate from ATP is endergonic.

Answer 111

False

Question 112

T or F: Once phosphates are released from ATP they can be added back in an endergonic reaction.

Answer 112

True

Question 113

T or F: The creatine-Phosphate to creatine reaction has a AG of -11kcal/mole and thus can be used to generate ATP from ADP.

Answer 113

True

Question 114

T or F: When ATP is hydrolyzed to form ADP, the energy is released into the cytoplasm where enzymes use it to run endergonic reactions.

Answer 114

False

Question 115

Anabolic reactions ___ NADH and ATP

Answer 115

Consume

Question 116

Catabolic reactions ___ NADH and ATP

Answer 116

Produce

Question 117

Molecules are broken down in ___ reactions

Answer 117

Catabolic

Question 118

Molecules are synthesized in ___ reactions

Answer 118

Anabolic

Question 119

Metabolic pathway

Answer 119

One enzyme activates another enzyme, which activates another enzyme A 6-carbon molecule is converted into a 5-carbon molecule, which is converted into a 4-carbon molecule

Question 120

Not a metabolic pathway

Answer 120

A collection of unrelated enzymes at the plasma Enzyme Q breaks down substrate A into products X, Y, and Z Enzyme P can have two possible substrates, R and S