CBS Flashcards by Olivia Cuddy

SER function?

Biosynthesis of lipids and sterols
n-linked glycosylation
detox of xenobiotics
(functions are tissue specific)

How well did you know this?

Not at all

Perfectly

RER function?

Protein synthesis and protein folding

How well did you know this?

Not at all

Perfectly

Cytoplasm function?

aqueous solution with precise pH and ion composition

site of metabolic reactions

How well did you know this?

Not at all

Perfectly

Nucleus function?

site of genetic material, replication and transcription

How well did you know this?

Not at all

Perfectly

Plasma membrane function?

boundary for cell, selective transport and signalling

How well did you know this?

Not at all

Perfectly

Golgi body function?

modification and packaging of proteins for export/sub-cellular compartments

How well did you know this?

Not at all

Perfectly

Lysosome function?

autophagy and cell turnover

How well did you know this?

Not at all

Perfectly

Peroxisome function?

detoxification, phospholipid synthesis, production and degradation of hydrogen peroxide and long chain fatty acid oxidation

How well did you know this?

Not at all

Perfectly

Mitochondria function?

ATP synthesis, TCA and fat oxidation

How well did you know this?

Not at all

Perfectly

Cytoskeleton function?

mechanical strength, controls cell shape, guides cell movement

How well did you know this?

Not at all

Perfectly

What is chromatin?

DNA organised into chromosomes -> a complex of DNA, histones and other proteins

How well did you know this?

Not at all

Perfectly

Nucleous function?

rDNA transcription, ribosome subunit assembly

How well did you know this?

Not at all

Perfectly

Which organelles are visible by light microscopy?

nucleus and mitochondria

How well did you know this?

Not at all

Perfectly

What are the 4 main classes of biomolecules?

carbohydrates, nucleic acids, proteins and lipids

How well did you know this?

Not at all

Perfectly

Which orientation is alpha and beta glucose?

alpha has OH group facing down, beta has it facing up

How well did you know this?

Not at all

Perfectly

How are glycosidic bonds formed?

2 monosaccharides are joined by glycosyltransferase

Produces disaccharide and water

How well did you know this?

Not at all

Perfectly

What makes up the 3 disaccharides?

sucrose = glucose + fructose
maltose = glucose + glucose
Lactose = glucose + galactose

How well did you know this?

Not at all

Perfectly

What is the basic nucleotide structure?

phosphate group + pentose sugar + base

How well did you know this?

Not at all

Perfectly

What is the structure and function of triacylglycerol?

3 fatty acids + glycerol

energy storage in adipose tissue

How well did you know this?

Not at all

Perfectly

what are the structures of protein?

primary structure = amino acid sequence
secondary structure = a-helix and b-sheets
tertiary structure = 3d folding of polypeptide
quaternary structure = subunit assembly

How well did you know this?

Not at all

Perfectly

What are the different type of amino acid side chain interactions?

disulphide bridges, hydrogen bonds, ionic bonds, van der Waals forces, hydrophobic effect

How well did you know this?

Not at all

Perfectly

What are class 1 enzymes - oxoreductases

add o2 or remove 2H

- e.g. lactate dehydrogenase

How well did you know this?

Not at all

Perfectly

What are class 2 enzymes - transferases

transfer functional groups

- e.g. alanine amino transferase

How well did you know this?

Not at all

Perfectly

What are class 3 enzymes - hydrolases

catalyse hydrolytic reactions

- e.g. tripsin

How well did you know this?

Not at all

Perfectly

What are class 4 enzymes - lysases

- add groups to C-C bonds | - e.g. ATP-citrate lysase

What are class 5 enzymes - isomerases

- catalyse isomerisation | - e.g phosphoglycose isomerase

What are class 6 enzymes - ligases

- form new covalent bonds using ATP | - e.g. DNA ligase

What are isoenzymes?

different enzymes that catalyse the same reaction | e.g. lactate dehydrogenase

What is the michaelis menton constant?

Km = (K-1 + K2)/ K1 | low Km = high affinity

What is the michaelis-menton equation?

V0 = Vmax[S] / (Km + [S])

What are the assumptions of the michaelis-menton equation?

1. there is much more [S] than [E] 2. ES formation = ES breakdown (steady-state) 3. Inital velocities are used

What can you find from a michaelis-menton plot?

``` Vmax = max height of graph Km = 1/2 Vmax ```

How is efficacy of an enzyme calculated?

Kcat/Km

What values of Kcat and Km do you want for an enzyme?

High Kcat | Low Km

What is the lineweaver-burke plot used for?

to determine Km & Vmax experimentally

What does a lineweaver-burke plot indicate?

``` 1/Vmax = y-intercept -1/Km = x-intercept ```

How do inhibitors alter Km/Vmax?

Competitive alter Km (increase it) | Non-competitive inhibitors decrease Vmax

what is pH

meaasure of H+ concentration | = -log[H+]

what is the pH range in blood?

7.35-7.45

what is the living range of pH?

7.0-7.8

what is the pH range in urine?

5.0-8.0

what is a buffer?

a solution that resists large swings in pH by releasing H+ or accepting H+

what is pKa?

the pH where half the acid is dissociated | = -log[Ka]

what is the henderson-hasselbach equation?

pH = pKa + log[A-]/[HA]

what is the main buffer in blood?

haemoglobin (due to histamine residues)

what is the pKa of haemoglobin?

oxy Hb = 6.8 | deoxy Hb = 7.8

What is the structure of a phospholipid?

polar head (serine, choline etc), phosphste group, glycerol backbone, 2 fatty acid chains

What factors affect membrane fluidity?

chain lengths - short chains increase fluidity saturation - more double bonds increase fluidity cholesterol - decreases fluidity

How can integral proteins be removed from a membrane?

by detergent

How can anchored proteins be removed from a membrane?

by detergent and phospholipases

How can peripheral proteins be removed from a membrane?

by detergent, phospholipase or high salt solution

What is the structure of haemoglobin?

tetrameric haem protein | 2 alpha and 2 beta chains

What is the structure of foetal haemoglobin?

2 alpha and 2 gamma chains

What proteins are targeted via the ER?

lysosomal, membrane and secreted proteins

What proteins are translated in the cytosol?

nuclear, mitochondrial and peroxisomal proteins

What are the steps of protein synthesis in the ER?

1. ribosome initiates synthesis 2. SRP recognises the signal sequence on protein 3. SRP binds receptor on ER membrane 4. Protein is guided through translocon into ER lumen 5. Signal sequence is cleaved

How do vesicles fuse with membranes?

V-SNARE on vesicle binds with T-SNARE on membrane

What moleucle is required for targeting proteins to the mitochondria?

Chaperones e.g. HS70

What directs protein targeting to the nuclues?

Nuclear localisation signal (NLS) binds to importin

How does protein targeting to the lysosome occur?

proteins are tagged with mannose-6 phosphate receptor on golgi directs proteins into vesicles vesicle matures into lysosome

What is a disease affecting lysosomes?

I-cell disease | mannose 6 phosphate mutation

what are the units of actin?

``` filaments = f-acint monomers = g-actin ```

What is the structure of actin?

double helix with a positive and negative end

How do actin filaments grow?

g-actin is added and removed at each end | binds ATP to be added

What are some examples of intermediate filaments?

lamina, keratin, neurofilaments

What is the structure of microtubules?

long, stiff hollow tubes | made of alpha and beta tubulin monomers

What affects the rate of diffusion?

Kow - partition coefficient

How do ions move through an ion channel?

selectivity filter - hydration shell which is sensitive to the ion's radius

What are the features of GLUT1?

``` low Km (high affinity) mainly in RBCs and BBB ```

What are the features of GLUT2?

high Km in pancreatic beta cells and hepatocytes triggers insulin release

What are the features of GLUT3?

low Km | in neurones

What are the features of GLUT4?

in muscle and adipocytes | insulin binding triggers GLUT4 to move to plasma membrane

What is GLUT5?

fructose transporter

What is a drug that inhibits the Na+/Ca2+ transporter

ovabain | used in heart failure - triggers contraction

What is SGLUT1?

Na+/glucose transporter used to absorb glucose in intestines targeting in cholera therapy

What is the signalling pathway involving PLC?

Gq -> PLC -> DAG + IP3 IP3 opens Ca2+ channels in the ER DAG and Ca2+ activate PKC