Physiology Flashcards

1
Q

What does it mean by the plasma membrane being fluid?

A

It can change its shape easily. Many proteins in the membrane can diffuse laterally, but many are anchored so it is important to realise that many proteins are not distributed equally within the cell membrane.

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

What is the structure of a plasma membrane ?

A

It is a bio-molecular layer of amphipathic phospholipid molecules with their hydrophilic heads at the outer and inner surfaces and their hydrophobic fatty acid chains facing towards the middle

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

What are found in the plasma membrane ?

A

Cell attachment proteins
Receptors
Enzymes
Channels
Transporters

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

What is cytosol made of?

A

Proteins
Carbohydrates
Electrolytes
It has fluid and gel-like properties

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

What are the common features of a eukaryotic cell?

A

Outer membrane
Cytoskeleton
Cytosol
Membrane bound organelles
Inclusions

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

What is the cell membrane permeable and non-permeable to ?

A

It is permeable to oxygen,water, hydrophobic molecules and small molecules and non-permeable to charged molecules like sodium and potassium.

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

What is the function of the plasma membrane ?

A

It separates the cytoplasm from the outside environment.

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

How can an organelle be defined?

A

Small membrane bound organ that has a specific function and structural organisation that is important to maintain life.

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

What are examples of membrane bound organelles?

A

Mitochondria
Rough endoplasmic recticulum
Smooth endoplasmic recticulum
Golgi apparatus
Lysosomes
Nucleus

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

What are inclusions?

A

Inclusions in a cell are small, non-living substances or particles found inside the cell.

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

Name some Inclusions in the cell?

A

Glycogen granules
Lipid droplets
Pigments

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

What is the cytoskeleton?

A

The cytoskeleton is a network of protein fibers inside a cell that gives the cell its shape, supports it, and helps it move. It acts like the cell’s “skeleton” and “muscles,” providing both structural support and flexibility.

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

What does the cytoskeleton do?

A

The cytoskeleton also plays a role in transporting materials within the cell and helps organize its internal components.

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

What is the cell membrane permeable to?

A

small hydrophobic molecules
water
oxygen

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

What defines a eukaryote?

A

Any cell or organism that possesses a clearly defined nucleus

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

What is a plasmalemma?

A

It separates the cytoplasm from the outside environment , that forms a selectively permeable barrier

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

What is cell membrane impermeable to?

A

charged ions

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

What can be found in cytoplasm ?

A

organelles and inclusions

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

What does the mitochondria do?

A

produces energy production(energy house)

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

What does the rough ER do?

A

synthesises proteins

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

What does smooth ER do?

A

synthesise lipids and cholesterol
and detoxifies

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

What does Golgi apparatus do?

A

modification and packaging of secretions

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

What do lysosomes do?

A

hydrolytic enzyme for intracellular digestion

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

What does the nucleus do ?

A

contains genetic code

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is an example of inclusions?
adipose cells in brown fat
26
What are microfilaments composed of?
2 actin strands
27
What are microtubule composed of ?
alpha and beta tubular that form protofilaments -> form microtubule
28
What are MAPS?
Microtubule associated proteins
29
What is dynein and what does it do?
It is an ATPase, that moves toward the cell and drags the membrane of organelles and vesicles along the microtubule
30
What is kinesin and what does it do?
It is an ATPase, that moves toward the cell periphery and drags the membrane of organelles and vesicles along the microtubule
31
What is Euchromatin?
DNA that is more dispersed and undergoing transcription
32
What is heterochromatin?
DNA that is highly condensed and not undergoing transcription
33
Where does mRNA and tRNA synthesis take place ?
in nucleus
34
Where does rRNA take place?
in nucleolus(within nucleus)
35
What do nuclear pores do?
allow the transport of molecules across the nuclear envelope
36
Where are ribosomes formed?
in nucleolus
37
What do cristae do and where can they be found?
In mitochondria, they increase the surface area
38
What does the mitochondria do?
produce ATP through oxidative phosphorylation, and is involved in creating certain lipids and proteins
39
What do intracellular junctions do?
connect cells to other cells, happens mainly in epithelial cells
40
What are occluding(tight) junctions?
links cells to form a diffusion barrier and prevents diffusion aka Zona occludens
41
What is an anchoring junction?
aka adherens junction, it anchors cells together and prevents separation
42
What are desmosomes?
they link sub-membrane intermediate filaments of adjacent cells aka macula adherens
43
What does a communicating (gap) do?
allow movement of molecules between cells (selective diffusion)
44
How do communicating gaps look like?
each junction is studded with several pores, these pores are produced by connexion proteins
45
What are communicating gaps used for?
ions and cytokines pass between cells-> rapid communication
46
Where can communicating gaps be found?
smooth muscle cardiac muscle epithelia -> used for spread of excitation
47
How can material move across the cell membrane ?
Diffusion transport proteins(pumps and channels) Incorporation into vesicles(requires ATP)
48
How does vesicular transport occur?
Endocytosis Exocytosis Phagocytosis
49
What is endocytosis?
It is a receptor mediated process that incorporates extracellular material into the cell
50
What is exocytosis?
it expels intracellular material out of the cell
51
What is phagocytosis?
Bacteria binds to the cell surface and the cell engulfs it to the phagosome that then binds with lysosome containing digestive enzymes which produce a phagolysosome
52
How long does a cell cycle last for skin cells?
for days
53
How long does the cell cycle last for liver cells ?
for years
54
How long does the usual cell cycle last?
about 12 hours
55
What are the stages of a cell cycle?
G1, S ,G2
56
What parts is the cell cycle divided into?
Mitosis and Interphase
57
What phases are in the interphase?
G1, S, G2
58
What are cyclins?
cyclins are proteins and their concentration increases and decreases throughout the cell cycle
59
What are the cell cycle proteins called?
cyclins A, B and E
60
What is the role of cyclins during the cell cycle?
cyclins activate cyclin dependant kinases(CDKs)
61
What happens to cyclin and CDKs when cell cycle is complete?
cyclins and CDKs are degraded and absorbed by ubiquitin(cytoplasmic care taker protein)
62
What phases is the interphase made up of?
G1, S, G2
63
What does the nucleus contain?
It is inside a nuclear envelope and contains network of chromatin threads, granules and nucleolus
64
Where does replication of DNA take place ?
In the nucleus
65
Where are the two paired centrioles located?
In the cytoplasm
66
What is the G1 phase about?
GROWTH PHASE Also called the growth phase or gap phase
67
What happens in G1 phase?
It is the time when the cell initiates another cycle most of the molecular machinery is created during G1 that will be needed in the next phase of the cycle Organelles synthesise proteins and make energy
68
How is the G1 phase controlled?
it is controlled through cyclin E and CDKs
69
What happens at the end of G1 phase?
It is also the check point for DNA damage which would result in apoptosis
70
What is the S phase about ?
DNA REPLICATION DNA replication happens in this cycle
71
Explain what happens in S-Phase?
DNA is synthesised
72
What is S phase promoted by?
promoted by cyclin A and CDKs
73
What does the S phase end with?
Two identical daughter copies
74
What is the G2 phase about ?
cell prepares for division and this period ends with the breakdown of nuclear membrane and onset of chromosome condensation
75
What is G2 phase controlled by?
Cyclin B and CDKs
76
What happens after G2 phase?
Mitosis and cytokinesis
77
Name the different phases of Mitosis?
Prophase Prometaphase Metaphase Anaphase Telophase (Cytokinesis)
78
What happens in Prophase?
Nuclear membrane disintegrates chromosomes first visualised and split into longitudinally into 2 chromatids
79
What happens in the Prometaphase?
Nuclear membrane and nucleolus disappear Chromosomes are entangled in a meshwork of continuous microtubules
80
What happens in Metaphase?
Chromosomes align at the metaphase plate. Colchicine arrest: cell division at metaphase prevents the formation of microtubules of the spindle
81
What is the role of colchicine?
arrests the cell division at metaphase prevents the formation of microtubules of spindle
82
What can colchicine be used for?
karyotyping cytotoxic drugs in cancer therapy
83
What happens in Anaphase ?
Spindle fibres contract, causing the sister chromatids to separate and reach the opposite poles of the cell
84
What is the end result of Anaphase?
Two identical complete chromosomes
85
What is non-disjunction?
when one or more chromosomes fail to migrate properly in anaphase, so one daughter cell receives extra chromosomes and the other is deficient in chromosomes
86
What are Isochromosomes?
the formation of two daughter cells of unequal length due to the centromere splitting transversely instead of longitudinally
87
What happens in Telophase?
nuclear membrane reforms and nucleolus appears Cytoplasm divides and two complete cells are formed
88
What is cytokinesis?
the cleavage furrow develops around the equator region and daughter cells separate
89
What happens in the G0 phase?
The cell is resting
90
What is the role of the nucleus?
Store DNA Protect DNA Regulate what enters and exits cells Plays a role in DNA processes Regulate cell division Regulate immune response
91
What does the cytoskeleton do?
allows movement of organelles and of the cell itself, gives shape and can change shape involved in cellular movement involved in cell division and muscle contraction
92
What is the cytoskeleton?
a network of proteins within the cell that determines shape and fluidity of cell
93
What is the result of the mitotic cell division?
Two genetically identical daughter cells
94
Describe the different stages in mitosis in short form?
Prophase: Chromosomes condense and spindle fibers form. Metaphase: Chromosomes align in the center of the cell. Anaphase: Sister chromatids are pulled apart to opposite sides of the cell. Telophase and Cytokinesis: The cell divides its cytoplasm, forming two new daughter cells.
95
What are the 4 basic tissue types?
Epithelial Connective Muscle Nervous
96
What are common features of epithelial cells?
strong adhesion between epithelial cells minimal intercellular space formation of sheets of cells
97
What other features do epithelial cells have ?
have a basal surface(basal laminae) which is a layer of the extracellular matrix components
98
What do cells attach to?
cells attach to the basal laminae and vary in size, shape, orientation and function
99
What do epithelial cells cover ?
cover surfaces of the body, lines, hollow organs and forms glands
100