question

Terms used to describe shape

answer

Coccus pl cocci,
bacillus, pl; Bacilli,
Spirillum

question

• Structural differences between Gram positive and Gram negative cell wall

answer

Gram positive cell walls contain teichoic acid, have thick peptidoglycan layer, Lack outer membrane, lipopolysaccharide and porin proteins

question

Why are electrons important in metabolism?

answer

The movement of electrons helps cells make ATP

question

Know difference between:
Chemotroph vs. Phototroph

answer

Chemotrophs use chemical compounds for their energy source
Phototrophs use light as their energy source

question

Why is nitrogen fixation important to all life on this planet?

answer

Nitrogen fixation is important because cells use nitrogen to make amino acids and nucleic acids.
-Done by converting N2 to amino acids in a process of deamination.

question

Obligate aerobe

answer

require oxygen for growth

question

Facultative Aerobe

answer

Can live with or withut O2

question

Obligate anaerobe

answer

grows without the presence of O2

question

Aerotolerant

answer

can grow in the presence of oxygen but do not use it as its final electron acceptor.

question

Microaerophile

answer

Organisms that require small amounts of oxygen for growth but are inhibited by larger amounts.

question

What is a mutation

answer

• A mutation is a change in the nucleotide sequence of a cells DNA

question

Spontaneous mutations include

answer

Base substitution
removal or adding nucleotides
transposable elements

question

Three results of base subtitutions

answer

A silent mutation- Nucleotide change results in when new amino acid results in wild amino acid.
Missense mutation results when new codon encodes for a different amino acid.
Nonsense mutations. Occur when the changed codon is a stop codon.

question

What are two structures that are found in some, but not all, viruses?

answer

A matrix protein and an envelope.

question

Anti-sense DNA can be used to make what?

answer

Sense + DNA

question

Describe the basic structural differences between bacteriophage and animal viruses.

answer

Bacteriophage have tail region that are used to inject genetic material into host.
Animal virus enters host cell directly and can have additional outer coverings such as matrix protein and envelope.

question

What’s the function of the tail structure in bacteriophage?

answer

The tail structure attaches to the host cell and injects the viral nucleic acids into host.

question

• What’s an operon?

answer

An operon is a group of genes whose expression is controlled as a single unit.

question

The genes of the lactose operon encode for proteins that do what?

answer

Encodes for proteins required for degradation of lactose.

question

cellular metabolism

answer

breaking down and building up of molecules in order for cell to stay alive.

question

Molecules needed for a cell to live

answer

-Needs a molecule containing high energy electrons.
- molecule that has pull for electrons
-molecule containing carbons
N, S, P, Fe, Mg

question

Catabolic reactions

answer

break down molecules

question

anabolic reactions

answer

build molecues

question

Organic molecules

answer

Have H AND C (has to have both to be organic

question

Inorganic

answer

Lack H or C or both

question

Chemoorganotroph

answer

Use organic molecules as electron source.
Ex. Carbs, proteins, lipids

question

chemolithotroph

answer

Use Inorganic molecules as electron source.
H2 H2S NH3

question

Phototroph

answer

Use low energy inorganic and organic.
make high energy from sun

question

Respirator

answer

perform respiration

use inorganic molecules as electron acceptor.

O2, NO3, SO4

question

2 types of respiration

answer

aerobic respiration uses O2 as final electron acceptor

Anaerobic respirator uses NO3, SO4

question

Fermentator

answer

uses organic molecules as final electron acceptor

Ex: Pyruvate

question

Autotroph

answer

uses inorganic molecules as its source of carbon.
CO2

Auto (self)
troph(Feed)

question

heterotroph

answer

use organic molecules such as lipids, carbs, and proteins

question

Cells that can metabolize organic molecules and O2

answer

chemoorganotroph heterotroph fermentator aerobic respirator

question

glucose is valuable because

answer

it contains carbons
because it has high energy electrons.

question

Lac Z encodes for

answer

Beta-Galactosidase
A protein that serves as an enzyme that breaks up the glucose and galactose

question

Lac A encodes for

answer

Beta-galactoside transacetylase.

is the third protein that enables the bacteria to break down lactose.

question

Lac Y encodes for

answer

Galactoside permease
a pore protein that allows the E. coli to take the lactose in.

question

(lac operon)
What’s the function of CAP-cAMP?

answer

Helps RNA polymerase bind to the promoter region

question

(lac operon)
What’s the function of the operator region?

answer

A binding site for the repressor protein keeping the lac operon turned off

question

What’s the function of the lac I gene

answer

Contains information to tell the cell how to make the repressor protein.

question

The presence of lactose causes E. coli to turn ( on or off ) its lactose operon and why?

answer

On. The repressor protein changes shape when it comes in contact with lactose and falls off the operator region allowing the RNA polymerase to transcribe the lac operon. Which then produces the proteins that metabolize lactose.

question

The presence of glucose causes E. coli to turn ( on or off ) its lactose operon.

answer

Off.

In order to make ATP the AMP is used up leaving none available to bind to the cAMP. The Camp in turn changes shape rendering it unable to bind to the DNA molecules releasing the RNA polymerase from the promoter region shutting down the lac operon.

question

How does the presence of lactose cause the lactose operon to get turned on?

answer

The repressor protein changes shape when it comes in contact with lactose and falls off the operator region allowing the RNA polymerase to transcribe the lac operon. Which then produces the proteins that metabolize lactose.

question

Bacteria Vs Virus

answer

Bacteria are living, viruses are not.
Viruses lack ribosomes, ATP, ways of making ATP. No free floating AA or NA

question

Basic structure of a virus

answer

Nucleic acids wrapped in a protein coat.(capsid)
Some have a matrix protein and an envelope made up of phospholipids

question

A virus that infects bacteria

answer

bacteriophage

question

Ways viruses can differ

answer

Some contain Single stranded nucleic acid
some have double stranded NA's
Some have segmented NA, some have Non-segmented NA
Some have RNA
Some have DNA

question

two types of infection caused by bacteriophage

answer

Latent- don't produce complete viruses
productive- complete viruses are produced

question

nuclease

answer

encodes for nuclease enzyme that breaks down chromosomal DNA in the host cell.

question

polymerase

answer

reads NA and makes compliment of it.

question

Early genes

answer

Viral genes expressed immediately after entering the host cell. Part of productive infection

question

two types of infection caused by Animal viruses

answer

Latent
Productive

question

HIV

answer

has NA made of RNA

question

(hiv)Viral RNA?
Process called?

answer

is used to make complimentary DNA strand reverse transcription

question

Animal viruses leave host cell via

answer

Budding. Gains envelope by doing this.
lysing the cell

question

Retrovirus

answer

virus that does transcription in reverse.
Makes DNA from RNA

question

two receptors needed for HIV gp120 to bind to and infect host cell

answer

CD4 and a co-receptor (CxCR4 on helper T cells Or CCR5 found on macrophages, and dendritic cells)

question

What allows fusion to happen?

answer

GP40 embeds itself in the membrane of the host cell

question

Types of cells HIV can infect

answer

brain cells, MACs, Helper T-cells, Intestinal cells

question

hallmark of advanced HIV infection

answer

Low Helper t cells

question

How does HIV cause Helper T cells die due to osmotic pressure?

answer

Influx of NA and K ions which are co-factors required by enzymes for replication. This causes the cell to burst due to osmotic pressure.

question

a. proteins responsible for detecting DNA damage do whatb. If they are missing?

answer

a. stop the cell from dividing
. Cell cant detect if its DNA is damaged, it will kill itself

question

viral protein R (Vpr)

answer

deactivates protein responsible for detecting damaged DNA

question

apoptosis

answer

cell mediated cell death

question

Infected (helper T cell)CD4 molecule

answer

loads antigen onto mhc 1 and presents to cytotoxic T cell. Cytotoxic T-cell recognizes antigen as foreign and kills the cell.

question

GP120 causes decrease of helper t cells by?

answer

binds to cd4 molecules keeping them from patrolling the blood for cells that need help

question

free floating GP 120

answer

binds to cd4 molecule of helper T cell causing antibodies to bind which then attracts Natural killer cells triggering ADCC (cell death)

question

On average the time it takes for Hiv to overtake CD4 cells

answer

is about 4 years

question

-HIV infects
-causing

answer

-CD4+ cells
-immediate depletion of CD4 cells

question

Hiv infections decreases in the beginning because?

answer

cytotoxic t cells and antibodies are able to respond and kill the infected cells.

question

As number of CD4 cells go down...
causing???

answer

-Cells are not able to release cytokines that activate cytotoxic T cells.
B-cells are not activated, so less antibodies are produced.

question

four classes of drugs to treat HIV

answer

1: Fusion inhibitors
2: reverse transcriptase inhibitor (stops DNA expression of HIV genome)
3: Inegrase inhibitor. Prevents HIV DNA from being intagrated into host DNA.
4: protease inhibitors. Prevent HIV from producing fully functioning proteins

3:

question

Hiv is hard to target once it is inserts into DNA of host.

answer

Because there are no drugs to target DNA without damaging host.

question

attenuated vaccines

answer

are weakened live viruses. HIV has high mutation rate and can mutate back to wild form.

question

Inactivated vaccines

answer

are dead viruses, Produces insufficient immune response. Doesn't work against all strains of HIV

question

HIV GP120 epitopes

answer

are hidden from antibodies by carbohydrate molecules. Keeping b-cells from binding and antibodies from being produced.

question

Why inactivated HIV vaccines don't work against all strains.

answer

Because HIV has a high mutation rate.

question

Sub-unit vaccine

answer

uses portions of the virus. Has same problems as inactivated virus

question

DNA vaccines

answer

-promising because you can use consistent HIV gene that does not differ between strains.

-stimulates both Ab and Tc responce
-Does not provie complete immunity
-not approved for use.

question

b cells and t cells

answer

are part of adaptive immune response

question

Innate Immune Cells (macrophage and neutrophil)

answer

ability to fight pathogens is encoded for by genes that don't change.

Built in immune system.

question

Adaptive immune cells

answer

can change (adapt) after coming into contact with pathogen.
Possess genes that are more prone to change.

question

all blood cells come from....

answer

come from hematopetic stem cells

question

Common lymphoid progenitor

answer

gives rise to cells in the adaptive immune system

question

hematopetic stem cells are found in

answer

the red bone marrow of the thymus, hips, tops of legs and shoulders.

question

two types of lymphoid organs

answer

-Primary lymphoid organs (bone marrow and thymus)

Secondary lymphoid organs: Lymph nodes, lymphatic, vessels, appendix, spleen and peyers patches. Secondary LOs are where pathogens are brought together with leukocytes.

question

B-cells

answer

bind to free floating epitopes.
Takes in Antigen, chops it up and presents it to helper t cell. Helper t cell confirms foreign antigen, releases cytokines and which activates B-cell

question

T cells

answer

only bind to epitopes if they are being presented by another cell.because TCR only recognizes epitope and MHC as a combo

question

What happens when B-cells become activated?

answer

B cell makes clones of itself. Some become Memory B cells and some become plasma cells. Plasma cells release antibodies specific to the antigen that originated the cloning of origional B-cell.

question

Memory B cells have _______ cytokine receptors than original

answer

More. this makes them more efficient should they encounter antigen again.

question

When antibodies stick to a bacterial cell........

answer

-can prevent bacterial cell from binding to our own cell (neutralization)

-can result in compliment proteins to become activated

- NK cell can binds to antibodies bound to antigens and causes ADCC

-agglutination

question

ADCC is?

answer

Antibody dependent cell mediated cytotoxicity

question

helper t cells activate..

answer

B cells, macrophages, NK cells and cytotoxic T cells.

question

CD4 Molecules are found on..
CD8 Molecules are found on..

answer

a helper T cells
B Cytotoxic T cell

question

Cytotoxic T cells releasecausing the cell to die how? why?

answer

perforins and proteases.
By apoptosis.
Lysing the cell would release the virus with in the cell. apoptosis makes the cell shrivel up and be eaten by a macrophage.

question

Some viruses avoid being killed by cytotoxic T-calls how?

answer

by down regulating the expression of the MHC 1 molecule in the host.

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