Biochem - SBAs

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2 sources of glucose in the body:

Diet and Liver

A buffer is...

A chemical compound that helps to stabilise the pH of a solution by removing or adding protons

A prosthetic group is defined as

Non-protein component bound to a protein for its activity

A protein domain is defined as

An independent folded structure within a polypeptide with an independent function

Acidic amino acids carry a

Negative charge (Lose H+)

An enzyme with a high Km has a

Low affinity

An example of a peripheral membrane protein is

Spectrin

An inhibitor stops working when substrate concentration is increased x1000. What kind of inhibitor is it?

Competitive

Collagen is a

Fibrous protein

Conversion of phosphoenol pyruvate into pyruvate is the last reaction of glycolysis. This reaction is catalysed by:

Pyruvate Kinase

Disulfide bonds can be formed by

Cysteine

Example of an aromatic amino acid includes

Phenylalanine

Example of an imino acid includes

Proline

How do you work out pH

-log(H+)

If deltaG for a reaction is positive, the reaction is said to be

Endergonic

If deltaG is close to 0 what affects the reaction

Concentration of substrate and enzyme

In competitive inhibition

Km increases but Vmax remains the same

In competitive enzyme inhibition, Km

Always goes up

Insulin secretion is stimulated by

Parasympathetic

Ions travel across the plasma membrane

Via facilitated diffusion or active transport with carrier and channel aids

Irreversible inhibition involves

Covalent interactions

Keratin is a

Fibrous protein

PDC catalyses the conversion of pyruvate into

Acetyl CoA

Porins can be found in

Gram negative cell wall

Presences of an imino acid in a polypeptide sequence induces formation of

A bend

Protein domains are formed in

Tertiary structure

Pyruvate dehydrogenase complex is made up of what three enzymes

Lipoamide reductase transacetylase, dihydrolipolyl dehydrogenase, pyruvate decarboxylase

Reversible inhibition involves

Non-covalent interactions

Secondary structure of proteins involves

Hydrogen bonds

Some polymers contain cross links. What are cross-links

Chemical bonds between different chains in a molecules (e.g. adjacent chains in a polymer). In proteins they are formed as disulphide bridge

Sugar acids are monosaccharides that have

A hydroxyl group oxidized to a carbonyl group

Tertiary structure of proteins involves

non-covalent interactions

The amount of an acid or base that can be added to a volume of a buffer solution before its pH changes significantly is defined as

Buffer capacity

The carbonic acid concentration in the mouth is approximately

1.3mMol/L

The majority of amino acids in the body are

The organelle in which complex carbohydrates such as GAG's are synthesized in

Golgi apparatus

The pk value for amino group is

9.4

The pK value for carboxylic acid is

2.2

Two spatially distinct but chemically identical arrangements of atoms which are mirror images of each other are called

Stereoisomers

What amino acid causes a bend in a polypeptide chain

Proline

What are enterokinases

Enzymes produced by the mucosa of the small intestine. Its sole function is to active trypsinogen to trypsin

What does competitive inhibition do to the Km

Increases it

What is a zymogen

Inactive enzyme

What is an alpha carbon

Carbon to which the amino and carboxylic groups are attached

What is an example of oxidative deamination

Glutamate to aKG and NH3

What is the linkage for branching in glycogen

Alpha 1-6

What is the main buffer in stimulated saliva

Bicarbonate

What is the major buffer (amino acid) in humans at physiological conditions

Histidine

What is the major buffer in saliva

Carbonic Acid

What is the optically inactive amino acid

Glycine

What protein has a site for the formation of cross-bridges?

Fibrous proteins (Keratin) as it has large amounts of the AA Cysteine, which contain sulphur and so allow formation of cross-links via disul

Where is pyruvate converted to oxaloacetate

Mitochondria

Which AA has buffer properties

Histidine

Which amino acid causes a bend in the peptide chain

Proline

Which amino acid does not have an asymmetric carbon atom

Glycine

Which amino acid has a weakly acidic hydroxyl group

Tyrosine

Which amino acid is important in the buffering action of proteins at psychological pH values

Histidine

Which amino acid is not involved in the addition of sugars

Tyrosine

Which enzyme converts phosphoenolpyruvate to pyruvate

Pyruvate kinase

Which is a ketogenic amino acid

Lysine

Which is a system involved in homeostasis

Endocrine system

XXX reduces the enzyme effect but inhibition is 95% reversed when the substrate is increased by 1000 fold. What inhibition is this?

Competitive

Which best describes the space that the heart occupies

Middle mediastinum

What is the most abundant protein in the human body

Collagen

Alanine is a non-competitive inhibitor of

Pyruvate Kinase

Anomers are

Stereoisomers that have different orientation of hydroxyl at carbon one

Chymotrypsinogen is made up of

245 amino acids

Coupled reactions usually involve

Hydrolysis of ATP

Fatty acids get converted into acetyl CoA by

Beta-Oxidation

Glucokinase is found in

Liver

Glucose 6-phosphatase is predominantly found in

Liver

Glucose enters cells by

Glucose transporters

GLUT 2 is present on

Liver and pancreatic beta cells

GLUT 3 is present on

Plasma membrane

GLUT 4 is present on

Skeletal muscle and adipose tissue

Glycogen branches every

10 residues

Heparin is used as an

Anti-coagulant

How does lymph leave the lymph nodes

Efferent lymph nodes

How many ATP molecules are used in one turn of the urea cycle

3 ATPs

How many molecules of NADH are produced in glycolysis and the TCA cycle per glucose molecule

Glycolysis=2, TCA cycle=6

In anaerobic conditions what happens to pyruvate

Reduced to lactate

In gluconeogenesis pyruvate is converted to oxaloacetate in which cellular compartment

Mitochondria

In which direction does DNA synthesis take place

5' to 3'

Ketogenesis takes place in the

Liver

Malonate is a competitive inhibitor that inhibits

Succinate dehydrogenase

Maltose is a

Diasccharide

Metaphase is when

Centromeres of chromatids line up at the midline of the cell

N-acetyl sugars are made up of

Name a purine nucleoside

Guanosine

Negative nitrogen balance is

When protein degradation is greater than protein synthesis

Oxidative deamination involves

Conversion of glutamate into alpha-ketoglutarate and ammonia

Phenylalanine hydroxlase catalyses

Phenylalanine to tyrosine

Pyruvate dehydrogenate complex converts pyruvate to

CO2, NADH and Acetyl CoA

Pyruvate is converted into lactate by

Lactate dehydrogenase

Pyruvate is converted into PEP by

PEPCK, PC, MDH

Pyruvate kinase can be split into

PEP carboxykinase and pyruvate carboxylase

Rate limiting step for glycogen synthesis is

Glycogen synthase

Secondary diabetes mellitus does not arise from

Meningitis

Simplest GAG is

Hyaluronic acid

Starch branches every

24 residues

Structure of insulin molecule

Two polypeptide chains, A and B chains linked together by disulfide bonds

The cori cycle works between

Liver and skeletal muscle

The limiting factor for Krebs cycle is

Oxaloacetate

The number of disulphide bonds in chymotrypsinogen is

The role of DNA polymerase I and RNAse H is to

Replace RNA primers with DNA

The role of helicase is to

Separate the fragments

The role of RNA primase is to

Synthesises small portions of RNA primer required for initiation

What activates PFK-1

Fructose-3,6-bisphosphate and AMP

What amino acids are in the charge relay system in chymotrypsin

Serine, Histidine, Aspartate

What are phase 2 reactions

Conjugation

What are the sources of glucose for the body

Diet and Liver

What causes the release of lactate

Skeletal muscle

What do parafollicar cells secrete

Calcitonin

What happens in interphase

Prepare for mitosis

What is esterfication

Triacylglycerol synthesis

What is gluconeogenesis

Production of glucose from amino acids

What is glycogenolysis

Breakdown of glycogen in the liver

What is metaphase

When the centromeres line up at the equator

What is the function of calcitonin

Reduce blood serum levels of CA2+ and phosphate by increasing secretion of the ions and preventing bone resorption

What is the tRNA nucleotide sequence that specifies the AA methiosine that initiates the translation sequence

UAC

What occurs in anaphase

Identical chromosomes separate to poles

Where does glucokinase work

Liver

Wheres is glucose-6-phosphataase found

Endoplasmic Reticulum

Where is pyruvate carboxylase found?

Mitochondria

Which enzyme converts PEP to pyruvate

Pyruvate kinase

Which enzyme is involved in the phosphorylation of glucose

Hexokinase

Which glycosaminoglycan is used as an anti-coagulant

Heparin

Whcih glycosaminoglycan is used for the treatment of osteoarthritis

Chondroitin sulphate

What is an enzyme for transamination reaction

Amino transferase

What is the main function of calcium

Bone and tooth formation

What is the main protein calcium is bound to

Albumin

What does fumarase reaction involve

Adding water molecule across a double bond

What reaction is known as claisen condensation

Citrate synthase

Calcitonin is a relatively small polypeptide which

Decreases bone resorption by inhibiting osteoclast activity and increases calcium excretion by the kidneys

Classic galactosemia is a genetically inherited disorder which is causes by

Absence of galactose-1-phosphate uridyltransferase

Which nucleoside is not found in the genome of a retrovirus

Thymidine

Recognition and attachment of the correct amino acid depends on an enzyme called

aminoacyl-tRNA synthetase

The function of the large subunit of RNA is to

Form peptide bonds

The function of the small subunit of RNA is to

Provide framework on which the codon can be matched to an anticodon

The nucleotides are linked by

Phosphodiester bonds

The phosphate groups in ADP and ATP are linked by

Phosphoanhydride bonds

What do beta-lactams effect

Joining of peptidoglycan subunits to form cell wall

What is a noctinamide

Two nucleotides joined together

What is uric acid produced from

Purines

Where does uric acid get produced

Liver

Where is epinephrine secreted from

Adrenal glands

Which amino acid is needed as an initiator for human DNA replication

Methionine

Which cells does ILGF stimulateto produce glucose into blood

Liver cells

Alkaptorunia occurs in response to

Malfunctioning of phenyalanine hydroxylase

Alpha cells in the pancreas are responsible for secreting

Glucagon

Deficiency of which vitamin causes scurvy

Vitamin C

Delta cells are responsible for secreting

Somatostatin

F cells in the pancreas are responsible for secreting

Pancreatic polypeptide

Familial hypercholesterolaemia occurs in response to

Reduced LDL receptors

Fructose intolerance occurs in response to

Absence of aldolase B

In which part of the body is vitamin D3 activated

Liver

Patient presents with bleeding gums and bruising, what vitamin deficiency?

Vitamin C

Von Gierke's disease occurs in response to

Deficiency of glucose 6-phosphatase

What enzyme is absent in galactosaemia

Galactose-1-phosphate uridyltransferase

What enzyme is deficient in Vom Gierke's disease

Glucose-6-phosphatase

What is the RDA of vitamin A for women

0.6mg

What disease is common in Wales - the typical 'fair hair and blue eyes' and causes mental retardation

Phenylketonuria (PKU)

Which vitamin is involved in vision

Vitamin A

Which vitamin is synthesised by intestinal bacteria

Why is it important to have vitamins in your diet

Because they are co enzymes

Conversion of Phosphoenol pyruvate into pyruvate is the last reaction of glycolysis. This reaction is catalysed by

Pyruvate kinase

Pyruvate dehydrogenase complex catalyses the conversion of pyruvate into

CO2, NADH and AcetylCoA

What is the Km of an enzyme

Strength of binding between substrate and enzyme