Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AH Biology > Unit 1 > Flashcards

Unit 1 Flashcards

1
Q

Why is the proteome larger than the number of genes?

A

More than one protein can be produced from a single gene as a result of alternative RNA splicing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where does post-translational modification take place?

A

Rough endoplasmic reticulum, Golgi apparatus and the target site of the protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What can make the set of proteins expressed by a given cell type change?

A

Metabolic activity of the cell, cellular stress, the response to signalling molecules and diseased versus healthy cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Isoelectric point

A

The pH at which the protein has no net charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Centrifugation separates substances in a liquid using their…

A

Density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

TL Chromatography separates mixtures eg amino acids by using…

A

Solubility of the different components

Speed that each solute travels along the chromatogram depends on its differing solubility in the solvent used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Affinity chromatography separates proteins using…

A

A highly specific interaction eg between an antigen and antibody

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Electrophoresis separates proteins and nucleic acids using…

A

Size (length/mass)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does the SDS- PAGE technique differ from other gel electrophoresis?

A

It gives all molecules an equally negative charge and so separates by size alone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Name of protein markers on an antigen

A

Epitopes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Polyclonal antibodies v monoclonal antibodies

A

PC antibodies bind with more than one type of antigen where as MC antibodies bind with only one type of epitope on the antigen and so are highly specific.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Example of an immunoassay technique

A

ELISA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Example of hazards in a lab

A

Toxic or corrosive chemicals, heat or flammable substances, pathogenic organisms and mechanical equipment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Risk

A

The likelihood of harm arising from exposure to hazard

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Linear dilution

A

Dilutions differ by an equal interval eg 0.1 0.2 0.3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Log dilution

A

Dilutions differ by a constant proportion eg.10-1 10-2 10-3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does a centrifuge separate substances of differing density

A

More dense components settle in the pellet, less dense components remain in the supernatant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe affinity chromatography

A

A solid matrix or gel column is created with specific molecules bound to the matrix or gel. Soluble target proteins in a mixture with a high affinity for these molecules, become attached to them as the mixture passes down the column. Other non-target molecules with a weaker affinity are washed out.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does gel electrophoresis work

A

Charged macromolecules move through an electric field applied to a gel matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do native gels separate proteins

A

These gels do not denature the molecule so that separation is by size, shape and charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are immunoassay techniques used for

A

To detect and identify specific proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe western blotting

A

A technique used after SDS-PAGE electrophoresis

The separated proteins from the gel are transferred onto a solid medium

The proteins can be identified using specific antibodies that have reporter enzymes attached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Bright-field microscopy

A

Commonly used to observe whole organisms, parts of organisms, thin sections of dissected tissue or individual cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Fluorescence microscopy

A

Uses specific fluorescent labels to bind to and visualise certain molecules or structures within cells or tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Describe Aseptic technique

A

Eliminates unwanted microbial contaminates when culturing micro organisms or cells

Involves the sterilisation of equipment and culture media by heat or chemical means

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Growth factors

A

Proteins that promote cell growth and proliferation

Essential for the culture of most animal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Method of achieving a suitable colony count

A

Serial dilution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Method to estimate cells numbers in a liquid culture

A

Use of haemocytometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Method for counting viable cells

A

Vital staining

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Proteome

A

Entire set of proteins expressed by a genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are non-coding RNA genes used for?

A

Transcribed to produce tRNA, rRNA and RNA molecules that control the expression of other genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How does the system of internal membranes affect eukaryotes

A

Increases the total area of membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Eukaryote surface area to volume ratio

A

Small due to their size

This means the plasma membrane of a eukaryote is too small to carry out all the vital functions carried out by membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Describe the endoplasmic reticulum

A

Forms a network of membrane tubules continuous with the nuclear membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Describe the Golgi apparatus

A

It is a series of flattened membrane discs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are lysosomes

A

Membrane-bound organelles containing a variety of hydrolases that digest proteins, lipids, nucleic acids and carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Function of vesicles

A

Transports materials between membrane compartments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Where are lipids and proteins synthesised

A

Endoplasmic reticulum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Difference between rough ER and smooth ER

A

RER has ribosomes on its cytosolic face while SER lacks ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Synthesis of lipids

A

Synthesised in SER and inserted into its membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Where does the synthesis of all proteins begin

A

Cytosolic ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Synthesis of cytosolic proteins

A

Synthesised in cytosolic proteins and these proteins remain in the cytosol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Function of the signal sequence transmembrane proteins carry

A

Halts translation and directs the ribosome synthesising the protein to dock with the ER forming RER

Translation continues after docking and the protein is inserted into the membrane of the ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Describe a signal sequence

A

A short stretch of amino acids at one end of the polypeptide that determines the eventual location of a protein in a cell

45
Q

What happens once the proteins are in the ER

A

They are transported by vesicles that bud off from the ER and fuse with the Golgi apparatus

46
Q

Major modification in post translational modification

A

The addition of carbohydrate groups

47
Q

Function of vesicles that leave the Golgi apparatus

A

Take proteins to the plasma membrane and lysosomes

Vesicles move along microtubules to other membranes and fuse with them within the cell

48
Q

What happens as proteins move though the Golgi apparatus

A

They undergo post translational modification

49
Q

Post translational modification

A

Molecules move through the Golgi discs in vesicles that bud off from one disc and fuse to the next one in the stack. Enzymes catalyse the addition of various sugars in the multiple steps to form the carbohydrates.

50
Q

example of secreted proteins

A

peptide hormones and digestive enzymes

51
Q

where are secreted proteins translated

A

ribosomes on the RER and then enter its lumen

52
Q

then where do translated secreted proteins go

A

the proteins move through the Golgi apparatus and are then packaged into secretory vesicles

these vesicles move to and fuse with the plasma membrane, releasing the proteins out of the cell

53
Q

what are many secreted proteins synthesised as?

A

inactive precursors and require proteolytic cleavage to produce active proteins

54
Q

what is proteolytic cleavage ?

A

another type of post translational modification

55
Q

how do the R groups of amino acids differ

A

vary in size, shape, charge, h bonding capacity, chemical reactivity

56
Q

four type of amino acids

A

basic, acidic, polar, hydrophobic

57
Q

how do different proteins have different functions

A

function is dependant on R group

58
Q

what is the primary structure

A

the sequence in which the amino acids are synthesised into the polypeptide

59
Q

3 main types of secondary structure

A

alpha helices, parallel or anti-parallel beta-pleated sheets and turns

60
Q

how does an alpha helix form?

A

twisting the polypeptide chain into a helix then stabilising with h bonds

61
Q

what type of beta pleated sheet is the most stable

A

antiparallel is more stable as h bonding is more optimal

62
Q

how is the conformation to tertiary structures stabilised ?

A

by interactions between R groups: hydrophobic interactions, ionic bonds, London dispersion forces and disulfide bridges

63
Q

describe a quaternary structure

A

exists in proteins with two or more connected polypeptide subunits

it describes the spatial arrangement of subunits

64
Q

what is a prosthetic group

A

a non-protein unit tightly bound to a protein and necessary for its function

65
Q

what are disulfide bridges

A

covalent bonds between R groups containing sulfur

66
Q

example of a prosthetic group

A

the ability of haemoglobin to bind oxygen is dependant upon the non-protein haem group

67
Q

what influences interactions of the R groups

A

temperature and pH

68
Q

how does temp impact interactions between R groups

A

Increasing temperature disrupts the interactions that hold the protein in shape; the protein begins to unfold, eventually becoming denatured

69
Q

how does pH impact interactions between R groups

A

The charges on acidic and basic R groups are affected by pH. As pH increases or decreases from the optimum, the normal ionic interactions between charged groups are lost, which gradually changes the conformation of the protein until it becomes denatured

70
Q

what is a ligand

A

a substance that can bind to a protein

71
Q

describe ligand binding

A

R groups not involved in protein folding can allow binding to ligands

binding sites will have complementary shape and chemistry to the ligand

as a ligand binds to a protein binding site the conformation of the protein changes.

72
Q

what happens after a ligand has bound to a protein

A

a change in conformation causes a functional change in the protein

73
Q

where do allosteric interactions occur?

A

between spatially distinct sites

74
Q

what causes the affinity of the other active sites for binding of subsequent substrate molecules to increase?

A

the binding of a substrate molecule to one active site of an allosteric enzyme

75
Q

what kind of structure do allosteric proteins have

A

quaternary

consists of multiple subunits

76
Q

how do allosteric proteins show co-operativity in binding

A

changes in binding at one subunit alter the affinity of the remaining subunits

77
Q

what is the second type of site allosteric enzymes contain

A

allosteric site

78
Q

role of a modulator

A

regulate the activity of the enzyme when they bind to the allosteric site

79
Q

what happens after the binding of a modulator

A

the conformation of the enzyme changes and this alters the affinity of the active site for the substrate

80
Q

example of co-operativity

A

the binding and release of oxygen in haemoglobin

Changes in binding of oxygen at one subunit alter the affinity of the remaining subunits for oxygen

81
Q

difference between positive and negative modulators

A

PM increase the enzymes affinity for the substrate whereas negative modulators reduce the enzymes affinity

82
Q

how does pH and temp influence the binding of oxygen

A

A decrease in pH or an increase in temperature lowers the affinity of haemoglobin for oxygen, so the binding of oxygen is reduced. Reduced pH and increased temperature in actively respiring tissue will reduce the binding of oxygen to haemoglobin promoting increased oxygen delivery to tissue

83
Q

the addition or removal of phosphate can cause …

A

reversible conformational change in proteins

common form of post translational modification

84
Q

role of protein kinase

A

catalyse the transfer of a phosphate group to other proteins

85
Q

describe binding of phosphate

A

the terminal phosphate of ATP is transferred to specific R groups

protein phosphates catalyse the reverse reaction

phosphorylation brings about conformational changes which can affect a proteins activity

the activity of many cellular proteins such as enzymes and receptors is regulated in this way

86
Q

adding a phosphate groups adds…

A

negative charges

ionic interactions in the unphosphorylated protein can be disrupted and new ones created

87
Q

describe peripheral proteins

A

they have hydrophilic R groups on their surface and are bound to the surface of membranes, mainly by ionic and hydrogen bond interactions

88
Q

how are integral proteins held in the phospholipid bilayer

A

regions of hydrophobic R groups allow hydrophobic interactions to hold the proteins

89
Q

what do integral membrane proteins interact with

A

interact extensively with the hydrophobic region of membrane phospholipids

90
Q

what do peripheral membrane proteins interact with

A

the surfaces of integral membrane proteins

91
Q

what can and cant pass through the phospholipid bilayer

A

ions and most uncharged polar molecules cannot

some small molecules such as oxygen and CO2 pass through the bilayer by simple diffusion

92
Q

facilitated diffusion

A

is the passive transport of substances across the membrane through specific transmembrane proteins

93
Q

describe channel proteins

A

Channels are multi-subunit proteins with the
subunits arranged to form water-filled pores
that extend across the membrane

most channel proteins in animal and plant cells are highly selective

94
Q

what allows cells to perform specialised functions

A

different cell types have different channel and transporter proteins

95
Q

how do some channel proteins allow or prevent diffusion

A

they are gated and change conformation to do this

96
Q

what are ligand - gated channels controlled by

A

binding of signal molecules

97
Q

what are voltage-gated channels controlled by

A

changes in ion concentration

98
Q

describe how transporter proteins transport

A

they bind to the specific substance to be transported and undergo a conformational change to transfer the solute across the membrane

99
Q

active transport

A

uses pump proteins that transfer substances across the membrane against their conc. gradient

a source of metabolic energy is required

100
Q

describe the pumps that mediate active transport

A

transporter proteins coupled to an energy source

101
Q

how do some proteins provide the energy for active transport and why

A

some active transport proteins hydrolyse ATP directly to provide the energy for the conformational change required to move substances across the membrane

102
Q

what hydrolyses ATP

A

ATPases

103
Q

what combines to form the electrochemical gradient for a solute carrying a net charge

A

the concentration gradient and the electrical potential difference

104
Q

what does the electrochemical gradient determine

A

the transport of the solute

105
Q

where does the SP pump get its energy from

A

ATP hydrolysis

106
Q

describe active transport in a SP pump

A

The pump has high affinity for sodium ions inside the cell; binding occurs; phosphorylation by ATP; conformation changes; affinity for sodium ions decreases; sodium ions released outside of the cell; potassium ions bind outside the cell; dephosphorylation; conformation changes; potassium ions taken into cell; affinity returns to start

107
Q

describe how ATP hydrolysis affects the SP pump

A

For each ATP hydrolysed, three sodium ions are transported out of the cell and two potassium ions are transported into the cell. This establishes both concentration gradients and an electrical gradient

108
Q

example of SP pump in humans

A

In the small intestine, the sodium gradient created by the sodium-potassium pump drives the active transport of glucose

SP pump is in intestinal epithelial cells

109
Q

glucose support in small intestine

A

The glucose transporter responsible for this glucose symport transports sodium ions and glucose at the same time and in the same direction

AH Biology (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions