Biology: Ch.1- The Cell

Question 1

what are the four fundamentals tenants of cell theory?

Answer 1

1. All living things are made of cells
2. The cell is the basic fundamental unit of life
3. All cells arise from other cells
4. Genetic information is carried in the form of deoxyribonucleic acid (DNA) and is passed from parent to daughter cell

Question 2

What is the function of the nucleus?

Answer 2

Stores genetic information and is the site of transcription

Question 3

What is the function of the mitochondria

Answer 3

involved in ATP production and apoptosis

Question 4

What is the function of the lysosomes

Answer 4

break down molecules ingested through endocytosis and cellular waste products
also involved in apoptosis

Question 5

What is the function of the rough endoplasmic reticulum

Answer 5

synthesizes proteins destined for secretion

Question 6

What is the function of the smooth ER

Answer 6

lipid synthesis and detoxification

Question 7

What is the function of the Golgi apparatus

Answer 7

packages, modifies, and distributes cellular products

Question 8

What is the function of the peroxisomes

Answer 8

break down very long chain fatty acids, synthesizes lipids and contribute to the pentose phosphate pathway

Question 9

A child is diagnosed with an enzyme deficiency that prevents the production of hydrogen peroxide. What would be the likely outcome of such a deficiency?

Answer 9

Peroxisomes are dependent on hydrogen peroxide for their functions, so an enzyme deficiency that results in the inability to form hydrogen peroxide would likely result in an inability to digest long chain fatty acids. These fatty acids would build up in peroxisomes until most of the cellular contents were displaced by oversized peroxisomes, ultimately resulting in cell death

Question 10

List three elements of the cytoskeleton

Answer 10

1. Microfilaments
2. Microtubules
3. Intermediate filaments

Question 11

What are the predominant proteins in microfilaments?

Answer 11

Actin

Question 12

What are the predominant proteins in microtubules?

Answer 12

Tubulin

Question 13

What are the predominant proteins in intermediate filaments?

Answer 13

differ by cell type- including keratin, desmin, vimentin and lamins

Question 14

How to cytoskeletal structures of centrioles and flagella differ?

Answer 14

centrioles: 9 triplets of microtubules around a hollow center
Flagella: 9 doublets on on the outsides with two microtubules on the inside

Question 15

Epithelial cells or connective tissue?: fibroblasts, which produce collagen in a number of organs

Answer 15

connective tissue

Question 16

Epithelial cells or connective tissue?: endothelial cells, which line blood vessels

Answer 16

Epithelial cells

Question 17

Epithelial cells or connective tissue?: alpha-cells, which produce glucagon in the pancreas

Answer 17

Epithelial cells

Question 18

Epithelial cells or connective tissue?: osteoblasts, which produce osteoid, the material that hardens into bone

Answer 18

connective tissue

Question 19

Epithelial cells or connective tissue?: chondroblasts, which produce cartilage

Answer 19

connective tissue

Question 20

How are archaea similar to bacteria? How are they different from bacteria?

Answer 20

similar:
i. both are single celled organisms
ii. lack a nucleus or membrane bound organelles
iii. contain single circular xsome
iv. divide by binary fission or budding
v. overall share a similar structure
different:
i. start translation with methionine
ii. contain similar RNA polymerases
iii. associate their DNA with histones

Question 21

What are the three common shapes of bacteria?

Answer 21

1. spherical- cocci
2. rod shaped- bacilli
3. spiral shaped- spirilli

Question 22

How do gram + and gram - bacteria differ?

Answer 22

Gram +: thick layer of peptidoglycan and lipoteichoic acid, contain no outer membrane
Gram -: thin layer of peptidoglycan and am outer membrane containing lipopolysaccharides and phospholipids

Question 23

How eukaryotic and prokaryotic flagella differ?

Answer 23

euk flagella: contain microtubules composed of tubulin, organized in a 9+2 arrangement
prok flagella: made of flagellin and consist of a filament, a basal body and a hook

Question 24

What are the three mxns of bacterial genetic recombination?

Answer 24

1. Transformation
2. Conjugation
3. Transduction

Question 25

What is transformation?

Answer 25

The acquisition of genetic material from the environment that can be integrated into the bacterial genome

Question 26

What is conjugation?

Answer 26

The transfer of genetic material from one bacterium to another across a conjugation bridge- a plasmid can be transferred from F+ cells to the F- cells, or a portion of the genome can be transferred from an Hfr cell to the recipient

Question 27

What is transduction?

Answer 27

The transfer of genetic material from one bacterium to another using a bacteriophage as a vector

Question 28

what are the four phases of the bacterial growth curve and what happens in each phase?

Answer 28

1. Lag phase: bacteria get used to environment; little growth during this time 2. Exponential (log) phase: bacteria use available resources to multiply at an exponential rate 3. Stationary phase: bacterial multiplication ceases as resources are used up 4. Death phase: Bacteria die as resources become insufficient to support the colony

Question 29

Why are viruses considered obligate intracellular parasites?

Answer 29

Viruses do not contain organelles, such as ribosomes; therefore, in order to reproduce and synthesize proteins, viruses must infect cells and hijack their cellular machinery

Question 30

Coronavirus, which causes the common cold, is described as an enveloped, single stranded positive-sense RNA virus. What does this description indicate about the virus?

Answer 30

The description indicates that the virus contains an outer layer of phospholipids with an inner capsid. Within the capsid, there is a single-stranded RNA that can be immediately translated to protein by the ribosomes of the host cell

Question 31

Briefly describe the pathway of retroviral nucleic acids from infection of a host cell to release of viral progeny

Answer 31

The nucleic acid enters as single stranded RNA, which undergoes reverse transcription (using reverse transcriptase) to form double stranded DNA. This DNA is transcribed to mRNA, which can be used to make structural proteins. This mRNA doubles as the viral genome for new virions. Once new virions are assembled from the structurl proteins and mRNA (ssRNA) genome, the virions can be released to infect other cells

Question 32

What are the differences between the lytic and the lysogenic cycle?

Answer 32

in the lytic cycle: bacteriophages replicate in the host cell in extremely high numbers until the cell lyses and releases the virions in the lysogenic cycle: the bacteriophage genome enters the host genome and replicates with the host cell as a provirus. At some point (after exposure to an environmental stimulus), the provirus leaves the host genome and can be used to synthesize new virions

Question 33

How do prions cause disease?

Answer 33

Prions cause disease by triggering a change in the conformation of a protein from alpha helix to a beta pleated sheet. This reduces the solubility of the protein and makes it highly resistant to degradation