BIOL 261 - FINAL EXAM SHORT ANSWER QUESTIONS

Identify the components of prokaryotic and eukaryotic cell structure giving examples of each including the function and description of each structure.

Prokaryotic cell components:

• Cell wall: provides structural support (e.g., peptidoglycan in bacteria)

• Plasma membrane: controls movement of substances in/out of cell

• Cytoplasm: site of metabolic activity

• Nucleoid: area containing circular DNA

• Ribosomes (70S): site of protein synthesis

• Plasmids: small, circular DNA, often carrying antibiotic resistance

• Flagella: for motility

• Pili: used in attachment and conjugation

Identify the components of prokaryotic and eukaryotic cell structure giving examples of each including the function and description of each structure.

Eukaryotic cell components

• Nucleus: contains DNA, site of transcription

• Mitochondria: ATP production

• Endoplasmic Reticulum (smooth and rough): protein and lipid synthesis

• Golgi apparatus: modification and transport of proteins

• Lysosomes: digestive enzymes for breakdown of waste

• Ribosomes (80S): protein synthesis

• Plasma membrane: regulates transport

• Cytoskeleton: structural support and transport

Recall the processes of replication, binary fission, transcription, translation, and conjugation in bacteria.

Replication?

DNA is copied using DNA polymerase; semi-conservative.

Recall the processes of replication, binary fission, transcription, translation, and conjugation in bacteria.

Binary fission?

asexual reproduction in bacteria; DNA replicated, cell elongates, divides into two identical cells.

Recall the processes of replication, binary fission, transcription, translation, and conjugation in bacteria.

Transcription?

DNA → mRNA using RNA polymerase in the cytoplasm (no nucleus in prokaryotes).

Recall the processes of replication, binary fission, transcription, translation, and conjugation in bacteria.

Translation?

mRNA → protein using ribosomes, tRNA brings amino acids.

Recall the processes of replication, binary fission, transcription, translation, and conjugation in bacteria.

Conjugation?

transfer of plasmid DNA via sex pilus from donor (F+) to recipient (F−) cell.

Identify the processes of transduction (general and specific), transformation and transfection.

General transduction?

bacteriophage accidentally packages host DNA and transfers it to another bacterium.

identify the processes of transduction (general and specific), transformation and transfection.

Specialized transduction?

phage integrates into host genome and upon excision takes some host genes with it.

identify the processes of transduction (general and specific), transformation and transfection.

Transformation?

uptake of free DNA from the environment by a bacterium.

identify the processes of transduction (general and specific), transformation and transfection.

Transfection?

introduction of foreign DNA into eukaryotic cells using chemical, physical or viral methods.

Differentiate lytic and lysogenic infections in bacteria and humans.

Lytic cycle (bacteria)?

virus infects, replicates rapidly, lyses the host cell (e.g., T4 bacteriophage).

Differentiate lytic and lysogenic infections in bacteria and humans.

Lysogenic cycle (bacteria)?

viral DNA integrates into host genome (prophage), replicates with host; can later enter lytic cycle (e.g., lambda phage).

Differentiate lytic and lysogenic infections in bacteria and humans.

Lytic (humans)?

active viral replication (e.g., influenza, HIV during acute phase).

Differentiate lytic and lysogenic infections in bacteria and humans.

Lysogenic aka latent (humans)?

viral genome persists, reactivates later (e.g., herpes simplex virus).

Recall the steps involved in the cloning of a gene of interest in E. coli.

1?

Isolate gene of interest

Recall the steps involved in the cloning of a gene of interest in E. coli.

2?

Cut gene and plasmid vector with the same restriction enzyme

Recall the steps involved in the cloning of a gene of interest in E. coli.

3?

Ligate gene into plasmid using DNA ligase

Recall the steps involved in the cloning of a gene of interest in E. coli.

4?

Transform E. coli with recombinant plasmid

Recall the steps involved in the cloning of a gene of interest in E. coli.

5?

Select for transformants (e.g., using antibiotic resistance)

Recall the steps involved in the cloning of a gene of interest in E. coli.

6?

Screen for expression or presence of gene

Recognize how mutations occur in bacteria and the possible results of the mutations including specific examples of mutagens.

Mutagens?

Can occur spontaneously or via mutagens

• Mutagens:

  • Physical: UV light (thymine dimers)

  • Chemical: nitrous acid, base analogs

  • Biological: transposons

Recognize how mutations occur in bacteria and the possible results of the mutations including specific examples of mutagens.

Mutation results?

Results:

• Silent mutation (no change in protein)

• Missense mutation (amino acid change)

• Nonsense mutation (premature stop codon)

• Frameshift mutation (insertion/deletion)

Differentiate classical and serological identification of bacterial, viral, fungal and parasitic human pathogens.

Classical identification?

Culture, staining (Gram stain, acid-fast), microscopy, biochemical tests

Differentiate classical and serological identification of bacterial, viral, fungal and parasitic human pathogens.

Serological identification?

Detect antigens or antibodies using tests like ELISA, agglutination, Western blot

• Faster, does not require culturing

Distinguish between innate, humoral and cell mediated immunity.

Innate immunity?

Non-specific, immediate

• 1st line of defense

• Includes physical barriers (skin), phagocytes, NK cells, inflammation, complement proteins

Distinguish between innate, humoral and cell mediated immunity.

Humoral immunity?

B cells produce antibodies specific to antigens

• Part of adaptive immunity

• Memory B cells provide long-term protection

Distinguish between innate, humoral and cell mediated immunity.

Cell-mediated immunity?

T cells target and kill infected or cancerous cells

• Part of adaptive immunity

• Helper T cells (CD4+) activate other immune cells

• Cytotoxic T cells (CD8+) destroy infected cells

Recall how food and water are made safe to consume.

Food safety?

Pasteurization (e.g., milk)

• Cooking to proper temperatures

• Refrigeration and freezing

• Preventing cross-contamination

• Canning and preservatives

Recall how food and water are made safe to consume.

Water safety?

• Filtration

• Chlorination (kills pathogens)

• UV treatment

• Monitoring for contaminants and pathogens (e.g., coliform testing)