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Prelim > CSB (wk 11-18) > Flashcards

CSB (wk 11-18) Flashcards

1
Q

what are the relative energy values of Carbd, Lipids and proteins as respiratory substrates

A

Carb- 15.8 kJg^-1
Lipid- 39.4 kJg^-1
Protein- 17 kJg^-1

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2
Q

why is there a difference in ergy values between carbs, lipids and proteisn as respiratory substrates

A

the difference in energy values is due to the number of hydrogen atoms present which is why fats have the highest energy value

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3
Q

Define Respiratory Quotient

A

ratio of CO2 production to O2 consumption

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4
Q

what are the equations for RQ

A

RQ = volume of CO2 given out in unit time/ volume of O2 taken in in unit time

RQ = moles or molecules of CO2 given out/ moles or molecules of O2 taken in

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5
Q

what are the RQ values of carb, proteins and lipids

A

RQ values

Glucose- 1.0

Protein- 0.9

Fatty Acid- 0.7

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6
Q

what are the similarities and differences between steroid structures

A

Similarities:
- 4 Carbon rings
- 3x 6C and 1x 5C ring
-Key in classifying as steroids:
- All contain an OH
- All Contain only C,H and O
- Big non-polar region (C-H)
- Head end - polar

Differences:
Different side chains on ‘tail’ end.

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7
Q

whats the structure of cholesterol

A

ampiphathic- hydrophillic and hydropobic regions
- Polar head group
- planar ring structure
- Non Polar hydrocarbon chain

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8
Q

whats the function of cholesterol

A
  • Cholesterol inserts into the bilayer with their hydroxyl groups hydrogen
  • at high temps, cholecterol decreases mobility
  • At low temperatures, cholesterol also has an opposite effect; it inhibits phase transition - Prevents the bilayer changing from a liquid state to a rigid crystalline state
  • Cholesterol molecules fit between the phospholipids, preventing them from coming together and crystallising at low temperatures
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9
Q

whats the difference bwteen HDL and LDL lipoproteins

A

LDL-

  • High levels of LDL may be retained within arteries and initiate the formation of atherosclerosis

HDL-

  • collect excess cholesterol from the cells and transport it to the liver, where it is excreted in the bile as bile salts and native cholesterol.
  • High HDL levels associated with lower CV disease in humans
  • Also deliver cholesterol to adrenal, ovary and testis for use in steroid hormone synthesis
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10
Q

what are some examples of sex hormones and their functions

A
  • Progesterone – Synthesised in adrenal cortex and ovaries/testes
    • Uterine conditions for development of the embryo
    • Prevents further ovulation
    • Development of mammary tissue for production of milk
  • Testosterone – Synthesised in testes/ ovaries in women
    • Development of male sex organs in foetus
    • Growth of accessory sex glands at puberty
    • Spermatogenesis
  • Oestrogen
    • Synthesised in ovary, placenta, adrenal cortex and testes
    • Regulation of female oestrous and menstrual cycles
    • Bone development / maintenance
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11
Q

what are some examples of corticosteroids and thier functions

A
  • Produced in the adrenal cortex
  • Mineralocorticoids-Regulates electrolyte balance (regulates salt and water balance)Increases blood volume and blood pressure
  • GlucocorticoidsRegulates glucose metabolismStimulates degradation of fats and proteinsFacilitates the Fight or flight responseInhibits DNA synthesisAnti-inflammatory effectsInhibition of immune system
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12
Q

what are the uses and side effects of corticosteroids

A
  • Corticosteroids (e.g. prednisolone)
    • anti-inflammatory actions/dose: asthma, lupus/MS, eczema (pruritis), arthritis (but NSAIDs more common)
    • Immunosuppressive dose: immune-mediated disease, some cancers (eg. Lymphoma)
  • Side effects – only take for short periods of time
    • Liver damage, bone marrow/immune suppression, insulin resistance, iatrogenic Cushings (hyperadrenocorticism)
  • Taper use
    • Must not stop steroid use suddenly
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13
Q

what are the different ways of admistering steroids

A

topical, oral, injection- IV

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14
Q

what are some of the roles of proetins in the biological system

A
  • defence- all antibodies are proteins.
  • structure- proteins are the main component of body tissues, such as muscle, skin, ligaments and hair (fibrous proteins - collagen, keratin)
  • Catalytic- all enzymes are proteins, catalyzing many biochemical reactions
  • signalling- many hormones and receptors are proteins
  • transport
  • geen regulatory
  • storage
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15
Q

what are some exsmples of fibrous proteins and their structure

A

structural protein
- parallel polypeptide chains held together by cross-links

  • insoluble
  • collagen – the main component of connective tissue such as ligaments, tendons, cartilage.
  • Keratin is the protein of hard structures- hair, horns, feathers, quills, and other skin appendages of animals.
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16
Q

whats the structure and some functions of globular proteins - examples

A

spherical shape

soluble because hydrophobic region is inside

  • transport- haemoglobin
  • enxymes- lipase, dna polymerase
  • hormones- oestrogen, insulin
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17
Q

whats the function of storage proteins + example

A

Act as stores of amino acids (for energy) or serve to store other small molecules or ions bound to the protein

Iron is stored in the liver by binding the protein ferritin.

Ovalbumin – chicken egg whites

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18
Q

whats the function of signalling proteins + example

A

Many growth factors and hormones, such as insulin, are proteins. They are extracellular proteins that transmit a signal from one cell to cells in other tissues.

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19
Q

whats the function of gene regularoty proteins + example

A

Regulate gene expression by binding to specific elements of DNA which permit/inhibit their transcription and/or translation i.e switch genes on/off.

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20
Q

what are the simolarities in structure between all amino acids

A
  • Amphoteric (act as base or acid)
  • Zwitterions (has both negative and positive ionic moiety)
  • Isoelectric point (pH at which zwitterion exists)
  • Soluble in water
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21
Q

how can polar or non polar amino acids be identified

A

Side chains can be polar or non-polar

  • Non-polar
    • Aliphatic hydrocarbon chain
    • aromatic Phenyl group rings
  • Polar
    • Hydroxyl groups
    • Amide groups
    • Thiol groups
    • Form hydrogen bonds
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22
Q

how can an amibo acid be ideentified as an acid or a base

A

Amino acids with an amide on the side chain do not produce basic solutions

23
Q

how is optical isomerism present in amino acids

A

Amino acids (except glycine) have a chiral α-carbon bonded to four distinct groups: an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom (-H), and a variable side chain (R group).

24
Q

define standard amino acids and give an example

A

Standard amino acids are

  • specified by the genetic code.
  • used by cells in protein synthesis
  • eg. serine
25
Q

define essential amino acids and give an example

A
  • must be supplied in the diet
  • cannot be synthesised by the organism
  • The number of essential amino acids varies between species
    • nine for humans
    • ten for dogs
    • eleven for cats
  • In ruminants, most amino acids are supplied by proteins from microbes of the fore-stomach therefore dont have ‘essential’ amino acids
  • eg. taurine / lysine
26
Q

define non essential proteins

A
  • Non-essential amino acids
  • can be synthesised in the body
  • are as necessary to the makeup of proteins and metabolic reactions as essential amino acids
27
Q

define conditionally essential amino acids and give an example

A
  • they are ordinarily not required in food
  • they may not be synthesised by the body in certain physiological or pathological conditions
  • Example:

Cysteine:

  • Normally: Synthesised from the essential amino acid methionine.
  • Conditionally Essential: In cases of prematurity, severe stress, or low methionine intake.

Glutamine:

  • Normally: Synthesised in sufficient amounts by the body.
  • Conditionally Essential: During illness, surgery, or intense physical stress (e.g., burns or infections).
28
Q

describe the primary structure of proteins

A
  • number and sequence of amino acids
  • The shape and behaviour of the protein depends upon its primary structure.
  • If the primary structure changes, ie when mutations occur, it can alter structure and cause disease
29
Q

describe the secondary structure of proteins

A
  • When the polypeptide chains start interacting at the backbone, it folds into peculiar structures such as alpha helices or beta pleated sheets
  • The backbone interactions are driven by hydrogen bonding
30
Q

describe the tertiary structure of proteins

A
  • 3d folding
  • Hydrophobicity is the driving force for protein folding.
  • Side chain interactions give stability to the tertiary structure
31
Q

describe the quaternary structure of proteins

A
  • Several polypeptide chains come together.
    E.g. dimer, trimer, tetramer etc
  • Characteristic 3D spatial arrangement
  • Held together by bonds
    • Hydrogen bonding
    • Disulphide bonds
    • Ionic bonds
    • Intermolecular forces
  • Many functional proteins (enzymes, transport molecules) adopt this form
32
Q

describe ionioc bonds

A
  • Electrostatic interaction – large electronegative difference
  • Form between permanently ionised groups e.g. amine & carboxylic acid groups
  • Broken by pH change
33
Q

describe hydrogen bonding

A
  • Weaker electrostatic interaction involving the dipole moment
  • H is shared between two relatively electronegative atoms e.g. N or O
  • Involve H bond donors & acceptors
  • Broken by high temperature or pH changes
34
Q

describe disulphide bonding

A
  • Occur between cysteine (Cys) molecules
  • Broken by reducing agents
35
Q

what are the ways of denaturing- bonds breaking

A

Heat:
- Temperature increases energy
- Disruption of hydrogen/ionic bonds

PH:
- (de)protonation of side groups
- Disrupt hydrogen/ionic bonding
- Loss of structure

Chemical:
- Detergents (eg Lauryl Sulfate / Dodecyl Sulfate / Triton)
- Disrupt hydrophobic core
- Reducing agents
- Break disulphide bonds –S-S- converted to reduced –SH -SH
b-mercaptoethanol
- Urea/guanidinium chloride (chaotropic agents)
- Disrupt protein stability
- Protein analysis

36
Q

what is a conjugated protein

A

A conjugated protein is a protein that functions in interaction with other non-peptide groups.

The non-amino portion is known as the prosthetic group.

37
Q

how are conjugated proteins formed and give some examples of modifications

A

conjugated proteins are formed via post-transitional modifications mostly in the endoplasmic reticulum and the golgi.

some modifications include,

  • phosphorylation, hydroxylation, methylation, acetylation
38
Q

describe glycoproteins (location, function, process, examples)

A
  • Protein + carbohydrate (prosthetic)
  • Integral membrane proteins- located on extra-cellular side of membrane
  • increases solubility
  • glycosylation (carb attaches to an OH group of protein)
  • N-linked glycosylation = carb to asparagine- endoplasmic reticulum
  • O-linked glycosylation= carb to serine or threonine- Golgi
  • examples: antibodies endocrine function- glycoprotein hormones, mucins
39
Q

describe lipoproteins

A
  • proteins in the lipid-free form
  • Transport of fatty acids and cholesterol through the bloodstream
  • Examples:
    VLDL (very low density lipoprotein)
    LDL ( Low density lipoprotein).
    HDL (high density lipoprotein ie “good”)
    Chylomicron
40
Q

describe phosphoproteins

A
  • protein + PO4
  • Serine, Threonine and Tyrosine phosphorylation is mediated by target selective kinases enzymes.
  • Phosphate is derived from ATP hydrolysis Increases negative charge of protein
  • Function as docking sites for other proteins/ cell communication and signalling (eg. after a receptor binds a hormone)./ enzymes and receptors can be switched on or off by phosphorylation
  • Eg: p53 protein is involved in the suppression of the cell cycle. I
41
Q

describe haemoproteins

A
  • iron (Fe2+)+ proteins
  • prosthetic haem group can reversiblycombine with anoxygenmolecule formingoxyhaemoglobin.
    • Eachhaemoglobin with its 4 haem groups can carry4 oxygenmolecules(eight oxygen atoms
  • Examples:
    • Haemoglobin – oxygen-carrying haemoprotein of red blood cells
    • Myoglobin – oxygen-carrying haemoprotein of muscle cells.
    • Cytochromes – membrane-bound haemoproteins that carry out electron transport and are found on mitochondrial inner membranes.
42
Q

describe metalloproteins

A
  • Common metalloproteins (includes haemoproteins) are enzymes with metal ions as part of their active site.
  • Eg. DNA polymerase catalyses the polymerisation of DNA and requires Mg2+ as a cofactor.
  • source- zinc magnesium
43
Q

describe opsin

A
  • retinol + protein
  • Opsins are a family of receptor proteins.
    When coupled to their prosthetic group, the chromophore retinaldehyde, different opsins form different photopigments which act as receptor molecules in the retina of the eye.
  • Examples:
  • rhodopsins - high-sensitivity photoreceptors found in rod cells and used for night vision,
  • cone opsins – (3 types) used in colour vision and have a lower sensitivity .

source- vitamin A, retinoid

44
Q

describe ubiquitin

A
  • Ubiquitin is a small (76aa) ubiquitous lysine rich protein (found in every eukaryotic cell type)
  • It is covalently conjugated to proteins that need to be broken down via its many lysine residues
  • The presence of ubiquitin bound to a protein sends that protein to the proteasome which functions to chew up the protein (proteolysis)
  • marker gene
45
Q

whats the fate of amino acids in the body after absorption in small intestine

A
  • After absorption, they can’t be stored as they have no inert storage form, as nitrogen is a source of reactivity.
  • to store proteins deamination would need to take cost which would require energy so it would be inefficient
46
Q

Roles of the liver in deamination

A
  • The amine group is removed from the amino acid, leaving behind a ketoacid.
  • That amine group can be transferred to another “ketoacid” to make another amino acid. This is known as transamination
  • Or that amine group can be converted to urea in the ornithine cycle
47
Q

role of the liver in transamination

A
  • Excess amino acids have their amine group removed and added to the corresponding ketoacid of a different amino acid
  • By doing this we convert the amino in excess into a ketoacid, and produce an amino acid that we are short in
  • For example: the enzyme ALT would convert EXCESS glutamic acid into the ketoacid alpha-ketoglutataric acid by removing the NH3 group. That amine group is attached to pyruvic acid to make Alanine
48
Q

role of theliver in urea formation

A
  • after deamination
  • In the hepatocytes of the liver, due to the high toxicity and solubility of ammonia (NH3), it is immediately converted into a less soluble and toxic substance - urea. This conversion is called the ornithine cycle.
  • The cycle produces Urea and water which is then sent to the kidney to be excreted from the body.
49
Q

role of the liver in energy production

A
  • The left over ketoacid can then be used for energy production.
  • For example the ketoacid from alanine, glycine, cysteine and serine can be used to form pyruvate.
  • eg. The ketoacid of asparate is oxaloacetate - krebs
50
Q

Differences in the excretion of nitrogenous waste between different species

A
  • aquatic invertebrates- ammonia- ammonotellic
  • mammals/amphbians- urea- ureotellic
  • birds, insects- uric acid- uricotellic
51
Q

Difference in the excretion of urea in ruminants and non-ruminants

A

Most animals can only use proteins as sources of Nitrogen for their own sources of amino acids.

But ruminants are able to use Non-protein-nitrogen (NPN) compounds like UREA as a source of nitrogen

ruminants do not consume a lot of protein

They can recycle the urea that they produce in their livers.

52
Q

what are the steps recycling urea in ruminants

A
  1. Urea Formation: Urea is synthesised in the liver as a by-product of protein metabolism.
  2. Urea Transport to the Rumen: Urea enters the rumen either through saliva or directly through the rumen wall- urea transport proteins
  3. Microbial Utilisation: In the rumen, urease-producing microbes break urea down into ammonia (NH₃) and carbon dioxide (CO₂). The microbes use ammonia, along with energy sources like carbohydrates, to synthesise amino acids and produce their own microbial proteins.
  4. Eventual use of microbial population: The microbial population in the rumen are eventually moved into the abomasum, where protein digestion will occur. The breakdown of these microbes provide the ruminant with proteins, which are hydrolysed to amino acids and absorbed into the blood stream.
53
Q

what are the major proteins

A
  • Albumin- reabsorption of tissue fluid
  • fibrinogen- coagulation of blood
  • clotting factors- haemostasis
  • enzymes- catalysis
  • globulins- defense, transport
54
Q
A

Prelim (10 decks)

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