Unit 2 Review: Biochemistry, Cell Biology, & Genetics Flashcards Preview

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Flashcards in Unit 2 Review: Biochemistry, Cell Biology, & Genetics Deck (56)
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1

The catalytic rate of an enzyme is MOST sensitive to [S] when:

When S is much lower than Km, steep curve

2

For an enzymatic reaction, If the concentration of substrate is 5mM and the Km is 2mM, what fraction of enzyme is bound to substrate?

5/7

[S] = 5 mM; Km = 2 mM
[S]/([S] + Km) = 5/(5+2) = 5/7

3

When is Km approximately equal to Kd (the dissociation constant) for the ES complex?

when K2 is much greater than K3

Kd = K2/K1
Km = K2+K3/K1

when K3 is small, both are roughly equal

4

which enzyme’s activity is more sensitive to the body’s concentration of glucose? Hexokinase, glucokinase, or activity is independant for both enzymes?

Hexokinase becomes saturated and reaches its Vmax at a low concentration.

Glucose is much more sensitive to changes in glucose concentration

5

The protease of an hiv strain that is highly resistant to a protease inhibitor will show what combinations of properties?

High Ki indicates that the protease is highly resistant to a particular inhibitor because that inhibitor does not bind tightly to it
A high kcat/Km (or at least a kcat/Km that is approximately equal to wild type) means that the protease is highly effective at catalyzing the reaction and producing product
The most resistant HIV strains have proteases that are resistant to inhibitors but still efficient at doing their job

6

Which aspect of the body’s response to blood vessel injury is affected by warfarin?

Localization of the clotting proteins to the site of injury

Warfarin inhibits a vit K-dependent enzyme that allows clotting proteins (factors II, VII, IX, X) to adhere to membranes at the injury site

7

two requirements for a coupled enzyme reaction

substrate in excess. the reaction that uses the enzyme in question must be slower. the second reaction must be much faster



Coupled enzyme assays are useful when the products of the reaction catalyzed by the enzyme of interest cannot be quantified easily (either because they’re similar to the substrates or difficult to detect)
You can use the products as substrate for a second reaction for which the products CAN be measured easily
In order for this to work, the second reaction must be very fast and all substrates must be present in excess

8

ALT

viral hepatitis

9

amylase

pancreatitis

10

creatine kinase

muscle disorders/MI

11

Lipase

pancreatitis

12

lactate dehydrogenase

liver disorders

13

acid phosphatase

metastatic prostate carcinoma

14

alkaline phosphate

bone disorders and obstructive liver disesae

15

Hydrophobic signaling molecules



Typically bind nuclear/cytoplasmic receptors

Bind cell surface receptors and typically activate gene transcription

Tend to have relatively short half lives

Do NOT need binding proteins to be carried throughout the blood, examples include steroids and thyroid hormones.

typically bind nuclear/cytoplasmic receptors



Carried by binding proteins
Relatively long half lives
Freely pass through cell membranes
Bind nuclear receptors- which activate gene transcription
Steroids, retinoids, thyroid hormones
Exception: eicosinoids which are hydrophobic, but bind surface receptors, short half life, function on inflammatory responses and clotting

16

eicosinoids

which are hydrophobic, but bind surface receptors, short half life, function on inflammatory responses and clotting

17

hydrophilic signaling molecules

Peptides, nucleotides, amino acids, growth factors
Do NOT need carrier molecules to transport through blood
Have shorter half lives
Bind cell surface receptors and can act through
Ligand-gated ion channels
Enzyme linked receptors
Catalytic receptors,
Trimeric G-protein-linked receptors

18

pemphigus results from

autoimmune attack of desmosomal cadherin

19

adherens junctions allow for the

oriented contraction of actin filaments across cells, which is used to form the neural tube during development

20

fibronectin

a dimer using disulfide bonds, self-associates into bundles and fibrils. Interacts with integrins. Plays role in loose connective tissue, blood clots, wound healing

21

laminin

interacts with type IV collagen, integrin and proteoglycans. Major component of the basal lamina

22

Bad-

BCL2-BCLX -

BAX -

Bad- pro-apoptotic, with no signals for the cell to grow (trophic factors). Bad is free to interact with Bcl2/Bclx

Bcl2/Bclx- anti-apoptotic, normally interact with and inhibits Bax. Interaction with Bad prevents interaction with Bax

Bax- pro-apoptotic, when NOT INHIBITED by Bcl2/Bclx, forms channels and leads to cytochrome c release into cytosol ->apoptosis

23

describe trophic factors and apoptosis pathway

1. No trophic factors -> Bad is free
2. Bad interacts with Bcl2/Bclx(located in mitochondrial membrane)
3. Bcl2/Bclx can no longer exert their inhibitory effects on Bax
4. Bax is free to promote cytochrome c release from mitochondria into the cytosol -> procaspases become caspsases -> APOPTOSIS

24

eosin does what?

is an acidic stain, binds basic structures such as cytoplasmic proteins

25

metaplasia
hypertrophy
hyperplasia
atrophy
dysplasia

change in cell type that can protect against stress
hypertrophy - change in size
hyperplasia - increase in number
atrophy - cell death
dysplasia - change in organization

26

hematoxylin

Hematoxylin is a basic dye and binds nucleic acids

27

collagen stains

reticular fibers stain

elastic fibers stain

macrophages stain

Collagen: Stains homogenously PINK with eosin

Reticular fibers: Stain BLACK with silver

Elastic fibers: Special stains, pico-orcein & resorcin fuchsin

Macrophages: Stain with trypan blue

28

CT in the head is derived from

neural crest cells

29

Ehlers-Danlos syndrome type IV is caused by

deficient type III collagen

30

Connective tissue in most of the body develops from

embryonic mesoderm

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