Unit 6

Question 1

Why aren’t viruses considered alive?

Answer 1

They do not reach all the characteristics of a living thing

Question 2

Which characteristics of living things (REACH N GO) do they NOT have

Answer 2

● Reproduce (they replicate)
● use Energy
● made of Cells
● maintain Homeostasis
● Grow (instead they assemble)
● not Organized

Question 3

What characteristics of living things DO they have

Answer 3

● Adapt / Evolve

● contain Nucleic Acids (DNA/RNA)

Question 4

What are the two general parts of a virus?

Answer 4

a) Nucleic Acid (DNA or RNA)

b) Protein capsid/coat

Question 5

What are the protein projections that stick out from a virus used for?

Answer 5

Antigens (proteins) that act as Keys used to unlock and enter/infect a cell.

Question 6

Explain a lysogenic infection

Answer 6

Lysogenic infection (HIV), occurs when a virus infects a cell but the cell does
not show symptoms and is generally unharmed. The cell continues to live and
divide, each time continuing to replicate the viral DNA

Question 7

If you start feeling ill from a virus, what type of infection do you have and why?

Answer 7

One begins to feel ill or show symptoms once a
Lytic infection begins because your cells are being
ruptured/destroyed (lysed) each time millions of
copies of the virus are released

Question 8

Why can’t an antibiotic be given to someone ill with a viral infection?

Answer 8

Viruses are not alive therefore they cannot be “killed”. Antibiotics work by damaging
living bacteria cells. Since a virus is not a cell, antibiotics are not effective.

Question 9

What are the characteristics of bacteria and what basic cell type are they considered?

Answer 9

Prokaryotic cells: simple, do not have a nucleus or complex organelles
Contain a Cell Wall, can be either heterotrophic or a variety of forms of autotrophic

Question 10

What are 3 general ways bacteria can be grouped together and what are the prefixes for this terminology?

Answer 10

a) Staphylo = clusters
b) Diplo = pairs
c) Strepto = chains

Question 11

What are the 3 general shapes of bacterial cells?

Answer 11

a) Bacilli = Rod shaped
b) Spirilla = Spiral shaped
c) Cocci = Sphere­shaped

Question 12

Explain WHY bacteria are able to live nearly everywhere

Answer 12

Bacteria are the smallest living cells, contain a rigid cell wall, can form endospores under extreme conditions,
and some can survive without oxygen.

Question 13

What is the role of bacteria in the ecosystem?

Answer 13

Decomposers – recycle energy, producers (oxygen), nitrogen fixers

Question 14

What are the three ways in which bacteria reproduce or exchange genetic material?

Answer 14

a) Binary Fission ­ simple cell division of prokaryotic cells
b) Conjugation ­ linking together to exchange genetic information
c) Endospore formation ­ forming a nearly indestructible barrier in order to
survive harsh environmental conditions

Question 15

During what type of conditions would bacteria begin to form endospores?

Answer 15

Harsh environmental conditions (drought, lack of food, toxins) causing the bacteria
species to die off.

Question 16

Why/How do bacteria harm us?

Answer 16

a) Deprive cells of nutrients (starve our cells) and secrete enzymes that break down tissue
b) Poison our cells by releasing toxins as waste. (endotoxins and exotoxins)

Question 17

What are the two general ways in which antibiotics kill bacteria?

Answer 17

a) Tear down cell walls

b) Disrupt formation of DNA / Inhibit protein synthesis (cellular processes)

Question 18

Which antibiotic worked the best in the picture above and how did you determine
your answer? (Underline the phrase, “Zone of Inhibition” in your answer)

Answer 18

Antibiotic A was the most effective because it has the largest zone of inhibition, which is the area around the
antibiotic disc where bacteria has been killed.

Question 19

How do we know that bacteria continually evolve? (Hint: Why must we keep formulating new antibiotics?)

Answer 19

Bacteria continue to evolve ways of becoming resistant to antibiotics. As their DNA mutates they are able to
be less affected by the ways in which the antibiotics work against them.

Question 20

Macrophage

Answer 20

Engulf pathogens

Question 21

B-­Cell

Answer 21

Produce antibodies

Question 22

Killer T-cell

Answer 22

Target and destroy body cells that have been infected

Question 23

Memory cells

Answer 23

WBCs that recognize the antigens on pathogens

Question 24

Antibodies

Answer 24

Bind to the antigens, mark for destruction and/or render ineffective

Question 25

Explain the two ways antibodies ​affect pathogens

Answer 25

a) Mark and clump together pathogens for destruction

b) Surround them and render ineffective. (neutralization)

Question 26

What is a vaccine and how does your body react to it?

Answer 26

Vaccines are inactive or partial pathogens that cannot actually make you sick yet allow
your body to produce antibodies that recognize the antigens present on their surface.

Question 27

What is true about your antibody levels the second time you are infected with a pathogen compared to the
first exposure? Why is this so?

Answer 27

Antibody levels are higher after the second exposure because memory cells
are able to recognize the pathogen and produce antibodies at a faster rate
which allows your body to fight the infection off before it has time to begin
spreading throughout the body.

Question 28

Using the picture to the right, when was the person given a vaccine
for Pathogen­A?

Answer 28

Vaccine was given during Week 2. The person then produced antibodies during week 3. Then in week 7
when the person became infected with Pathogen A, the person’s body already had made antibodies against it
due to the vaccine and was therefore able to fight off the infection before it began.

Question 29

Explain how we have used Bradford Assays and spectrophotometry to quantify concentrations of proteins
in patient samples?

Answer 29

Bradford reagent binds to proteins and turns blue. Therefore allowing us to quantify how many
proteins are in a sample based on light absorbance. By using a spec to measure (quanitify) light absorbance
we can quantify the concentration of protein