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Human Sciences 1 ( Year 0) > Cells And Enzymes > Flashcards

Cells And Enzymes Flashcards

1
Q

What is the three dimensional structure of a eukaryotic cell maintained by and what does it consist of

A

-cytoskeleton
-consists of interconnected protein filaments in the cytoplasm

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2
Q

What is the pH of the cytoplasm

A

7.2

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3
Q

What is the pH in extracellular fluid

A

7.4

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4
Q

What is the average diameter of a cell

A

10-20 microns

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5
Q

Why is it useful to use red blood cells to measure other cells

A

-have a diameter of 7 microns and are considered the smallest cells

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6
Q

Primary structure of a cell membrane is made up of ………….

A

Phospholipids

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7
Q

Phospholipids have a ……….. head and …………… tails

A

1.hydrophilic
2.hydrophobic

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8
Q

Why does health of the individual depend on the normal functioning of cells in the body

A

-Cells which don’t normally function can lead illnesses such as cancer or heart disease
-e.g. cancer is caused when cells divide uncontrollably and spread into surrounding tissues

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9
Q

What happens when you shake water and phospholipids together

A

Forms a micelle

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10
Q

what are the membrane components and how do they affect movement of substances across cell membranes

A

*PHOSPHOLIPID BILAYER
-Allows diffusion of non-polar small/lipid-soluble
molecules e.g. oxygen or water, down a concentration gradient
- Restricts the movement of larger/polar molecules
*CHANNEL PROTEIN
-allow diffusion of water soluble substances (facilitated diffusion)
*CARRIER PROTEINS
-allow diffusion of slightly larger substances (facilitated diffusion)
-allow active transport of substances against a concentration gradient
*CHOLESTEROL
-restricts movement of other molecules making up membrane -> decreases fluidity and permeability

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11
Q

Function of a nucleus

A

-Control centre of the cell
-responsible for transmitting genetic information and providing the instructions for protein synthesis

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12
Q

What is this organelle?

A

Nucleus

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13
Q

What is the function of ribosomes

A

-Protein synthesis- a place where mRNA is translated into protein.
-It contains rRNA and proteins

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14
Q

Which organelle is this ?

A

Ribosomes

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15
Q

What is the rough endoplasmic reticulum and its function

A

-Sugar groups are attached to proteins within the cisterns.
-Proteins are bound in vesicles for transport to the golgi apparatus and other sites.

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16
Q

Which organelle is this

A

Rough endoplasmic reticulum

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17
Q

What is the function of mitochondria

A

-Site of ATP synthesis; powerhouse of the cell.
-Energy production through aerobic metabolism and Ketogenesis

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18
Q

What is ketogenesis

A

A metabolic pathway that produces ketone bodies which provide an alternative form of energy for the body

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19
Q

Which organelle is this

A

Mitochondria

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20
Q

What is the Golgi apparatus and its function

A

-Group of fluid-filled membrane bound flattened sacs.
-Packages, modifies, and segregates proteins for secretion from the cell, makes lysosomes, and incorporation into the plasma membrane

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21
Q

Which organelle is this ?

A

Golgi apparatus

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22
Q

What are lysosomes and what are their functions

A

-Sites of intracellular digestion- contains enzymes called lysozymes.
-Can be used to digest invading cells or break down worn out components of the cell. pH= 4.8

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23
Q

Which organelle is this?

A

Lysosomes

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24
Q

What is the function of the smooth endoplasmic reticulum

A

Site of lipid and steroid ( choloesterol) synthesis, lipid metabolism and drug detoxification

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25
Q

Which organelle is this?

A

Smooth endoplasmic reticulum

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26
Q

What are the 3 cellular extensions

A

-cilia
-flagellum
-microvilli

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27
Q

What is a cilia

A

-each cilium is composed of nine pairs of microtubules surrounding a central pair.
-Coordinated movement creates a unidirectional current that propels substances across cell surfaces.

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28
Q

Which cellular extension is this?

A

Cilia

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29
Q

What is a flagellum

A

-Like cilium but longer
-e.g. in humans is the sperm cell and its function is to propel (move) the cell

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30
Q

Which cellular extension is this ?

A

Flagellum (sperm cell)

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31
Q

What is a microvilli and its function

A

-Tubular extensions of the plasma membrane; contain a bundle of actin filaments.
-It’s function is to increase SA for absorption

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32
Q

Which cellular extension is this

A

Microvilli

33
Q

What are the three immune system cells?

A

-macrophage
-plasma cells
- B cells

34
Q

What is a macrophage ?

A

-tissue based
-once they are activated, they kill pathogens
-secrete cytokines
-present antigens to T helper cells

35
Q

Which immune system cell is this?

A

Macrophage

36
Q

What is a plasma cell?

A

-they have eccentric nucleus
-they are differentiated from B cells
-they secrete antibodies

37
Q

Which immune system cell is this ?

A

Plasma cell

38
Q

What are B cells?

A

-develop in bone marrow
-have membrane bound antibody
-differenciate into plasma cells

39
Q

Which immune system cell is this?

A

B cells

40
Q

Name 4 cytoskeleton elements

A

-microtubules
-microfilaments
-centrioles
-intermediate filaments

41
Q

What are microtubules and their function

A

Support the cell and give it shape.Involved in intracellular and cellular movements. Form centrioles and cilia and flagella, if present

42
Q

Which cytoskeleton element is this?

A

Microtubules

43
Q

What are the functions of microfilaments

A

Involved in muscle contraction and other types of intracellular movement, help from the cell’s cytoskeleton

44
Q

Which cytoskeleton element is this

A

Microfilaments

45
Q

What are centrioles?

A

As part of the centrosome, organise a microtubule network during mitosis (cell division) to form the spindle and asters. Form the bases of cilia and flagella

46
Q

Which cytoskeleton element is this?

A

Centrioles

47
Q

What are intermediate filaments?

A

The stable cytoskeletal elements; resist mechanical forces acting on the cell

48
Q

Which cytoskeleton element is this?

A

Intermediate filaments

49
Q

What is a tissue?

A

Collections of cells to perform a function

50
Q
A
51
Q

Cells with special functions

A
52
Q

Name the three cells that connect body parts, form linings or transport gases

A

-epithelial cells
-fibroblasts
-erythrocytes

53
Q

Name the two cells that move organs and body parts

A

-skeletal muscle cell
-smooth muscle cells

54
Q

Name a cell that stores nutrients

A

Fat cell

55
Q

Name a cell that fights disease

A

Macrophage

56
Q

Name a cell that gathers info and controls body functions

A

Nerve cell

57
Q

Name a cell of reproduction

A

Sperm

58
Q

Endocrine cell

A
59
Q

-Most enzymes are ……….. soluble, ………….. proteins
-enzymes function as …………. …………
-most enzymes are highly specific- ………….. only one substrate or one type of substrate

A
  • water, globular
  • biological catalysts
  • recognise
60
Q

Enzymes lower ……….. energies

A

Activation

61
Q

What is activation energy ?

A

Minimum amount of energy that must be available to reactants for chemical reaction to occur.

62
Q

How do enzymes function?

A

By forming a complex with the substrate that stabilises it and lowers the activation energy

63
Q

Energy for reactions is provided by the hydrolysis of ….

A

ATP

64
Q
A
65
Q
A
66
Q

What is the active site ?

A

the complicated folding forms “clefts” of a particular shape on the surface of the enzyme

67
Q

What is meant by recognition?

A

the enzyme “recognises” a particular substrate that fits the shape of the active site

68
Q

What is meant by intermolecular forces?

A

Forces between separate molecules that hold the substance together

69
Q

Lock and key model

A
70
Q

Induced fit model

A
71
Q

Catalytic cycle of an enzyme

A
72
Q

Enzymes activity depends on three things….

A

-interactions with other molecules
-enzyme structure ( changes in pH and temperature)
-conc of the enzyme and substrate

73
Q

How is enzyme activity affected by interactions with other molecules?

A

-Can occur at active site or else where
On protein surface.
-Some interactions will inhibit, some will regulate

74
Q

Explain the graph

A
  • As pH increases / decreases above / below an optimum, rate of reaction decreases
    -Enzymes denature - tertiary structure and active site change shape
    -As hydrogen / ionic bonds break
    -So active site no longer complementary
    -So fewer E-S complexes form
75
Q

Explain this graph

A

-more enzyme molecules means more likely a substrate molecule is to collide with one and form a enzyme substrate complex
-if amount of substrate is limited, there’s more than enough enzyme molecules so adding more enzyme has no further effect

76
Q

Explain this graph

A

-more substrate molecules means a collision between substrate and enzyme is more likely and so more active sites will be occupied
-then all active sites become full so increase in substrate concentration has no further effect and its beyond saturation

77
Q

Explain this graph

A

-At low temp., rate is slow :molecules have low speeds and do not collide much and don’t have enough energy to overcome activation energy
-0°C - 40°C, enzyme activity increases with increasing temp. Molecules move faster and collide more and greater proportion of collision have enough energy to overcome activation energy.
-Above 40°C, majority of enzymes in the human body denature!

78
Q

Describe and explain the effect of concentration of competitive inhibitors on the rate of enzyme-controlled reactions

A

● As concentration of competitive inhibitor increases, rate of reaction decreases
-Similar shape to substrate
-Competes for / binds to / blocks active site
-So substrates can’t bind and fewer E-S complexes form
● Increasing substrate conc. reduces effect of inhibitors (dependent on relative concentrations of substrate and inhibitor)

79
Q

Describe and explain the effect of concentration of non-competitive inhibitors on the rate of enzyme-controlled reactions

A

● As concentration of non-competitive inhibitor increases, rate of reaction decreases
- Binds to site other than the active site (allosteric site)
- Changes enzyme tertiary structure / active site shape
- So active site no longer complementary to substrate
- So substrates can’t bind so fewer E-S complexes form
● Increasing substrate conc. has no effect on rate of reaction as change to active site is permanent

Human Sciences 1 ( Year 0) (10 decks)

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