Chapter 1 - The Cell Flashcards Preview

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Flashcards in Chapter 1 - The Cell Deck (35)
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1

Cytosol

What cell membrane is composed of.
Semi fluid cytosol - allows for diffusion of molecules throughout the cell.

2

Histones

Organizing proteins around which linear DNA is wound.

Package and order DNA into structural units called nucleosomes (grouped I to sets of 8, called histone octamers) Histones are the chief protein component of chromatin, acting as spools around which DNA winds. Play a role in gene regulation.

Histone -> histone octamer -> nucleosome -> chromatin

3

What is the cytoskeleton made up of (3)

1. Microfilaments (ACTIN)
2. Microtubules (TUBULIN)
3. Intermediate filaments

4

What are kinesin and dynein?

Motor proteins which pass along microtubules in the cell cytoskeleton

5

Centrioles

Found in centrosome.

Organizing centers for microtubules - organized in 9 triplets with a hollow centre.

During mitosis, centrioles move to opposite sides of the cell and organize the mitotic spindle.

6

Chromatid

One copy of a newly replicated chromosome (joined to the other copy by a single centomere)

7

Parenchyma

Functional parts of an organ

8

Examples of connective tissues:

Bone
Cartilage
Tendons
Ligaments
Adipose tissue
Blood

**CT often produces and secretes COLLAGEN and ELASTIN.

9

Archaea

Single-celled
Lack nucleus
Extremophiles

Start translation w methionine
Contain RNA polymerases
Associated DNA with histones

Known for using alternate sources of energy

10

Mutualistic symbiotes

When both humans and bacteria benefit from the relationship.

(Ie not a pathogen)

11

Gram positive cell wall

Thick peptidoglycan layer
Lipoteichoic acid (immune reaction)
No outer membrane

Stains crystal violet

12

Gram negative cell wall

Thinner peptidoglycan layer
Phospholipid and lipopolysaccharide outer membrane
(Lipopolysaccharide = immune resp, stronger than Lipoteichoic acid)

Stains SAFRANIN (red-pink) counterstain

13

Chemotaxis

Ability of a bacterial cell to detect chemical stimuli and move toward or away from it (via flagella)

14

Plasmids

Small DNA molecule, separate from the chromosomal DNA, that can replicate on it's own.

Linked with advantages such as antibiotic resistance.

Eg: sex factors are plasmids that contain the genes necessary for donor make bacteria to form the sex pili (appendage used for conjugation)

15

4 basic tenets of cell theory

1. All living things are composed of cells
2. The cell is the basic unit of life
3. Cells arise only from preexisting cells
4. Cells carry genetic info (DNA) from parent to daughter cell

16

Forms of genetic recombination (4) (ways for prokaryotes to obtain genetic information outside of binary fission)

1. Transformation
2. Conjugation
3. Transduction
4. Transposons

17

Episome

A subset of plasmids that is capable of integrating into the genome of the bacterium

18

Transformation (genetic recombination)

Integration of foreign genetic material into the host genome. Foreign material often come from lysis of other nearby bacteria.

Gram-negative rods are often able to carry out this process.

19

Conjugation (genetic recombination)

Sexual reproduction

Forming of a conjugation bridge between a donor male (+) and donor female (-) via "sex pili".

20

Transduction (genetic recombination)

Only one of these processes that requires a vector (virus that carries genes from one bacteria to another).

Bacteriophages (viruses that infect bacteria) can accidentally trap a segment of DNA during assembly. When it goes to infect another bacterium, it releases this trapped DNA into the new host cell, giving it additional genes.

21

Transposons (genetic recombination)

Genetic elements capable of inserting and removing themselves from the genome.

If a transposon is inserted within a coding region of a gene, that gene may be disrupted.

22

Bacterial growth phases (4)

1. Lag phase
2. Exponential phase (log phase)
3. Stationary phase
4. Death phase

23

Physical structure of a virus (5)

Genetic material (DNA or RNA, single or double stranded, linear or circular)

Protein coat (capsid)
Envelope containing lipids (sometimes)

Specific to bacteriophages:
Tail sheath (act as a syringe)
Tail fibers (recognize and connect to host cell)

24

Virions

Viral progeny produced by a virus once it has hijacked a cell's machinery. Virions are released to infect other cells.

25

Chromatin

Material of which the chromosomes of organisms other than prokaryotes (bacteria) are made of.

Consists of protein, DNA, and RNA.

26

What receptors do HIV viruses bind to on white blood cells?

CD4 and CCR5

27

What is a retrovirus

Enveloped
Single-stranded RNA virus
Carries enzyme called reverse transcriptase

28

What happens after a cell has been infected by a virus? (This is how the virus reproduces) IE where in the cell does it go?

TRANSLATION of genetic material

Viral DNA must go to nucleus
Gets transcribed to mRNA
mRNA goes to cytoplasm where it is translated to proteins (by the ribosomes)

+-sense RNA viruses go directly to the cytoplasm to become proteins

--sense RNA viruses need to make a complementary RNA strand via RNA replicate, and then can be translated to make proteins.

DNA from retroviruses goes to the nucleus where it can be integrated into the host genome.

29

What components are used to translate RNA into proteins?

Ribosomes
tRNA
Amino acids
Enzymes

30

3 ways for progeny release

1. Initiating cell death (spilling of viral progeny)
2. Lysis (of host cell due to too large numbers of virions)
3. Extrusion (like exocytosis) - allows virus to continue using haor cell to keep reproducing

**a virus in extrusion is said to be in a PRODUCTIVE CYCLE