1 Cell Biology Flashcards

1
Q

What is the composition of the cell membrane?

A

Lipid bilayer with protein channels, enzymes, receptors

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2
Q

What is the role of cholesterol in the cell membrane?

A

Increases membrane fluidity

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3
Q

What is the charge of the inside of the cell versus outside? What maintains this gradient?

A

Negative inside versus outside
Due to Na/K ATPase transporter
3 Na+ out/2 K+ in

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4
Q

How are glucose, proteins and other molecules transported across the cell membrane?

A

Via co-transport supported by the Na+ gradient

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5
Q

Components of extracellular fluid?

A
CATIONS:
Sodium - 140
Potassium - 4
Calcium - 5
Magnesium - 2
ANIONS:
Chloride - 103
Bicarb - 24
So4-2 - 1
HPO3-3 - 2
Protein - 16
Organic anion - 5
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6
Q

Component of intracellular fluid

A
CATIONS:
Sodium - 12
Potassium - 150
Calcium - 10-7
Magnesium - 7
ANIONS:
Chloride - 3
Bicarb - 10
So4-2 - -
HPO3-3 - 116
Protein - 40
Organic anion - -
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7
Q

Define desmosomes/hemidesmosomes

A

Adhesion molecules, which anchor cells

Cell-cell and cell-extracellular matrix

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8
Q

Define tight junctions

A

Cell-cell occluding junctions - form and impermeable barrier

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9
Q

Define gap junctions

A

Connexin subunits

Allow communication between cells

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10
Q

Define osmotic equilibrium

A

Water will move from an area of low solute concentration of higher solute concentration and approach osmotic equilibrium

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11
Q

What are the cell cycles - what occurs during them?

A

G1 (cell increases in size, checkpoint)
S (protein synthesis, chromosomal duplications)
G2 (cell increases in size, checkpoint)
M (mitosis, nucleus divides)

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12
Q

What is the most variable stage in the cell cycle?

A

G1 - affected by growth factors

Determines cell cycle length

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13
Q

What are the stages of mitosis?

A

Prophase - centromere attachment, spindle formation, nucleus disapears
Metaphase - chromosome alignment
Anaphase - chromosome pulled apart
Telophase - seperate nucleus reforms around each set of chromosomes

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14
Q

What is the composition of the nucleus?

A

Double membrane - outer membrane is continuous with the rough endoplasmic reticulum
Contains DNA

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15
Q

What is the composition of the nucleolus?

A

Inside the nucleus
No membrane
Ribosomes are made here

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16
Q

Define transciption

A

DNA stand is used as a template by RNA polyermase for the synthesis of a mRNA strand

17
Q

What are the purines?

A

Guanine, Adenine

18
Q

What are the pyrimidines?

A

Cytosine, thymidine (DNA), uracil (RNA)

19
Q

How do purines and pyrimidines bind?

A

Guanine forms 3 H-bonds with cytosine
Adenine forms 2 H-bonds with thymidine/uracil

AT CoG (for RNA switch a vowel with a vowel)

20
Q

Define translation

A

mRNA acts as template for ribosomes in the synthesis of protein

21
Q

Glycolysis - cost/outcome

A

2 glucose

2 ATP and 2 pyruvate molecules

22
Q

What is the composition of the mitochondria?

A

2 membrances
Krebs cycle on the inner matrix
Create NADH/FADH2

23
Q

Krebs cycle/ETC - cost/outcome

A

2 pyruvate molecules (from 1 glucose)
Multiple NADH, FADH2
ETC creates 36 ATP

24
Q

How does gluconeogensis work?

A

Lactic acid (via cori cycle) and amino acids are converted to glucose
Stress/starvation
Glycolysis in reverse

25
Q

Why can fat/lipids not used on gluconeogensis?

A
Acetyl CoA (breakdown product of fat metabolism)
Cannot be converted back to pyruvate
26
Q

What is the cori cycle?

A

Occurs in liver

Converts muscle lactate into glucose via pyruvate

27
Q

Rough endoplasmic reticulum

A

Synthesizes proteins for export

Prominent in pancreatic acinar cells

28
Q

Smooth endoplasmic reticulum

A

Synthesis lipid/steroids
Detoxifies drugs
(Prominent in liver and adrenal cortex)

29
Q

Golgi apparatus

A

Modifies proteins with carbohydrates

Allows for transport to the cellular membrane, secreted, or target to lysosomes

30
Q

Lysosomes

A

Contain digestive enzymes that degrade engulfed particles and worn-out organelles

31
Q

Phagosomes

A

Engulfed large particle that fuses with a lysosome

32
Q

Endosome

A

Engulfed small particle that fuses with a lysosome

33
Q

Protein kinase C

A

Activated by calcium and diacylglycerol (DAG)

Phosphorylates other enzymes and proteins

34
Q

Protein kinase A

A

Activated by cAMP

Phosphorylates other enzymes and proteins

35
Q

Define myosin

A

Thick filament

Uses ATP to slide along actin and cause muscle contraction

36
Q

Define actin

A

Thin filament

Provides the scaffold for myosin to move along in muscle contraction

37
Q

What are some intermediate filaments? Where are they found?

A

Keratin (hair, nails)
Desmin (muscle)
Vimentin (fibroblasts)