2.4: Proteins

Question 1

how many amino acids are there in polypeptides synthesized on ribosomes

Answer 1

20 different amino acids

Question 2

what bond links amino acids?

Answer 2

peptide bond

Question 3

formation of a dipeptide

Answer 3

from amino acids

Question 4

amino acid + amino acid –––––––>

Answer 4

dipeptide + water

Question 5

characteristics of R group in amino acids

Answer 5

• can be polar (hydrophillic)
• can be non-polar (hydrophobic)
• can be negatively or postively charged
• can contain sulfur

Question 6

what do characteristics of the R group do?

Answer 6

impacts the properties and behaviour of the protein

Question 7

what do ribosomes do

Answer 7

they are the molecule within cells that facilitate the formation of peptide bonds and thus they are whwere polypeptides are synthesized

Question 8

most organisms assemble polypeptides from the _________ amino acids

Answer 8

same

Question 9

why are there infinite possibilities of polypeptides?

Answer 9

• can be any length
• 20 amino acids
• amino acids in any order or combination
• basically limitless

Question 10

ribosomes aree the site of polypeptide synthesis, but ribosomes need a template– the ________________ which in turn, is ______________ by __________________ molecules, which, in turn, carry __________________.

Answer 10

messenger RNA
translated
transfer RNA
specific amino acids`

Question 11

Genes are….

Answer 11

codes for making polypeptides

Question 12

mRNA (messenger RNA) is…

Answer 12

a message from nucleus to ribosome
- gives intructions on how to put polypeptide together

Question 13

genetic code is…

Answer 13

the sequence of bases on mRNA
- tells ribosome which amino acids to use

Question 14

open reading frame

Answer 14

the base sequence that codes for polypeptide
- only occupy small portion of total DNA in species

Question 15

lysozome

Answer 15

• has one polypeptide
• enzymes in secreted biody fluids kills bacterial by breaking down the peptidoglycan in their cell walls

Question 16

collagen

Answer 16

• has three polypeptides
• strong, elestic structural protein found in connective tissues

Question 17

hemogoblin

Answer 17

• has four polypeptides
• transport protein in red blood cells
• binds oxygen from long and releases into tissues with lower oxygen concentration

Question 18

polypeptides are the _______________ of protein structure

Answer 18

base or primary level

Question 19

how different amino acids interact with each other and their surrounding determines…

Answer 19

their 3d shape

Question 20

before polypeptides are functional they must…

Answer 20

fold into specific structures based on the order/ structure of their amino acid sequence

Question 21

primary protein structure

Answer 21

sequence of a chain of amino acids

Question 22

secondary protein structure

Answer 22

hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern

Question 23

tertiary protein structure

Answer 23

three dimensional folding pattern of a protein due to side chain interactions

Question 24

quaternary protein structure

Answer 24

protein consiting of more than once amino acid chain

Question 25

shape: fibrous proteins vs globular proteins

Answer 25

fibrous proteins: - long and narrow globular protein: - rounded/spherical

Question 26

role: fibrous proteins vs globular proteins

Answer 26

fibrous: - structural - strength and support globular protein - functional - catalytic, transport etc

Question 27

solubility: fibrous protein vs globular protein

Answer 27

fibrous: - generally insuluble in water globular: - generally soluble in water

Question 28

sequence: fibrous protein vs globular protein

Answer 28

fibrous: - repetitive amino acid sequence globular: - irregular amino acid sequence

Question 29

stability: fibrous protein vs globular protein

Answer 29

fibrous: - less sensitive to chnages in heat, pH etc globular: - more sensitive to heat, pH etc

Question 30

examples: fibrous protein vs globular protein

Answer 30

fibrous: - collagen, myosin, fibrin, actin, keratin, elastin globularL - catalase, haemoglobin, insulin, immunoglobin

Question 31

The 3D conformation of protein is stabilized _____________________ between R groups of amino acids within the molecule

Answer 31

by bonds or interactions

Question 32

Most of these bonds are relatively weak, and can be _______________ with exposure to heat or changes in pH

Answer 32

disrupted or broken

Question 33

breaking or disrupting bonds results in a change to the ______________ of the protein, which is called __________ (usually permanent), this also causes a loss in ___________

Answer 33

conformation denaturation function

Question 34

renaturation

Answer 34

when protein regains its original 3D shape (and function) - can happen if the exposure is minimal, and the factor removed after a short time

Question 35

temperature on denaturation

Answer 35

- causes vibrations within the molecule that can break intermolecular bonds or interactions - Different proteins have different tolerances to heat

Question 36

pH on dentauration (too acidic or too basic)

Answer 36

- Changes the charges on R groups, breaking ionic bonds within the protein or causing new ionic bonds to form - Different proteins have different optimal pH values

Question 37

rubisco

Answer 37

- abbrev. for ribulose bisphosphate carboxylase - very important enzyme - catalyses reaction that fixes carbon fixes co2 from atmsophere - provides source of carbon that can produce carbon compounds - found in high concentration in leaves

Question 38

insulin

Answer 38

- hormone that gives signal to cells in body to absorb/reduce/regulate glucose conc. in blood - cells have receptor to let insulin to bind to - insulin is secreted in beta cells in pancreas

Question 39

immunogoblin

Answer 39

- aka antibodies - binds to antigens on bacteria/pathogens - casues response for phagocytes to engulf pathogens - basis for immunity to disease

Question 40

rhodopsin

Answer 40

- a pigement that absorbs light for vision - contains light sensitive molecule surrounded by opsin polypeptide - when it absorbs a single photon of light, it chnages shape, causing opsin to also change shape, leading to impulse being sent to brain

Question 41

spider silk

Answer 41

- conatains regions where polypeptides form parallel arrays - very exrensble and resistent to breaking

Question 42

proteome

Answer 42

all porteins made by a cell, tissue or organism

Question 43

genome

Answer 43

all the genes of a cell, tissue or organism

Question 44

proteome vs genome

Answer 44

proteomes are unique among individuals of same species, genome is not