The Cell

Question 1

Cell Theory

Answer 1

1. All living things are composed of cells
2. Cell is basic unit of life
3. Cells arise from pre-existing cells
4. Cells carry genetic information in form of DNA. Passed on from parent to daughter cell

Question 2

Nucleolus

Answer 2

Where ribosomal RNA (rRNA) is synthesized

Question 3

Lysosome and Endosomes

Answer 3

1. Contains hydrolytic enzymes, degrades substances ingested by endocytosis and waste material. May induce apoptosis
2. transport, package and sort cell material

Question 4

Where is lipid synthesized?

Answer 4

Smooth ER

Question 5

Golgi apparatus

Answer 5

Modifies cellular products by the addition of groups like carbohydrates, phosphates, and sulfates. Introduces single sequences which direct the product to specific cellular location

Question 6

Peroxisomes

Answer 6

Contain hydrogen peroxide. Breaks down long chain fatty acid via B-oxidation

Question 7

Microfilaments

Answer 7

Actin: solid polymerized rods organized in networks to provide protection to the cell
Work with myosin to produce muscle contraction
Play a role in cytokinesis

Question 8

Microtubules

Answer 8

hollow polymer of tubular

Kinesin (+/periphery) and dynein

Question 9

Cilia and flagella structures

Answer 9

Microtubules organizes in 9+2 structure

Question 10

Centrioles and Kinetochores

Answer 10

1. Located in centrosome, organization center of microtubules; mitotic spindle
2. Where microtubules attach on chromosomes

Question 11

Intermediate filaments

Answer 11

cell-cell adhesion, anchor organelles

Question 12

epithelial tissues

Answer 12

cover the body and line cavities
connected to basement membrane
constitute the parenchyma (functional part of organ)
polarized

Question 13

Where is the DNA of prokaryote located?

Answer 13

Nucleoid region.

Linear DNA

Question 14

Similarities between eukaryotes and archaea

Answer 14

1. Start translation with methionine
2. contain similar RNA polymerases
3. associate DNA with histones

Question 15

Similarities between bacteria and archaea

Answer 15

1. single circular chromosome
2. binary fission or budding
3. similar structure (contains flagella)

Question 16

Facultative anaerobes

Answer 16

can switch between aerobic and anaerobic metabolism

Question 17

aerotolerant anaerobes

Answer 17

unable to use oxygen for metabolism but are not harmed by O2 in the environment

Question 18

Gram positive bacteria

Answer 18

absorbs crystal violet stain (dark purple)
Consist of a thick layer of peptidoglycan (made of amino acids and sugars)
Contains lipoteichoic acid - human immune system reacts to it

Question 19

Gram negative bacteria

Answer 19

absorbs safranin (light pink)
thin peptidoglycan wall
Layer between cell wall and plasma membrane is called periplasmic space
Contain outer membranes containing lipopolysaccharides (trigger immune response)

Question 20

Does bacteria have histones?

Answer 20

No, their singular circular DNA is wrapped in histone-like proteins (but not histone)

Question 21

Prokaryotes ribosomes

Answer 21

30S and 50S subunits while humans have 40S and 60S.

These differences allows us to create antibiotics that target bacterial transcription only

Question 22

Binary fission

Answer 22

Asexual reproduction of prokaryotes

Singular circular DNA attaches to cell wall and gets replicate. Plasma membrane begins to grow inward and divide

Question 23

Bacterial transformation

Answer 23

integration of foreign genetic material into the host genome - absorb genetic info from bacteria that lysis

Question 24

bacterial conjugation

Answer 24

Sexual reproduction
Donor (+ F plasmid) attaches plus onto recipient (- F). Copy of sex factor is transferred. If sex factor was transformed into genuine then the entire genome may be transferred (high frequency recombination)

Question 25

Transduction

Answer 25

Virus carries genetic material (bacteriophages)

Question 26

Transposons

Answer 26

Genetic elements capable of inserting and removing themselves from the genome

Question 27

Bacterial growth curve

Answer 27

1. Lag phase: bacteria are getting used to new conditions 2. exponential phase (log phase): bacteria begin to reproduce 3. stationary phase: reduction of resources decreases rate of reproduction 4. death phase: bacteria have exceeded the ability of the environment to support it

Question 28

Viruses genetic information

Answer 28

circular or linear single or double stranded DNA or RNA

Question 29

Why do viruses require host cells?

Answer 29

they lack ribosomes to carry out protein synthesis

Question 30

Structure of bacteriophage

Answer 30

Capsid: protein coat surrounding DNA Tail sheath: acts as syringe Tail fiber: anchoring/ locomotion

Question 31

Positive sense virus

Answer 31

genome can be directly translated to functional proteins by ribosomes of host cell

Question 32

negative sense virus

Answer 32

RNA strand acts as a template for synthesis of complementary strand, which can be used as template for synthesis. Must carry RNA replicase

Question 33

Retroviruses

Answer 33

contains two identical RNA molecules. Uses reverse transcriptase to synthesize DNA from RNA. This DNA integrates into host genome --> permanently part of cell HIV

Question 34

Lytic cycle

Answer 34

Maximizes the use of cell's machinery with no regards to cell survival (lyses) Virulent viruses

Question 35

Lysogenic cycle

Answer 35

Genetic info integrates into hosts genome and it is replicated as the bacteria replicates (provirus)

Question 36

Prions

Answer 36

Infectious proteins that trigger the misfolding of other proteins (usually conversion of alpha to beta protein structures) Protein becomes insoluble and cell cannot degrade it --> aggregates and disrupts cell function

Question 37

Viroids

Answer 37

small pathogens that infect plants (HDV is a human example)

Question 38

Similarities bacteria and archaea

Answer 38

1. singular circular chromosome 2. divide binary fission or budding 3. similar overall structure