Topic 2 - Cells & Cancers Flashcards
(135 cards)
1
Q
What 3 things do all cells have in common?
A
A cell membrane
Cytoplasm
DNA
2
Q
What does the nucleus of the cell contain?
A
DNA
3
Q
What are the two categories of cells?
A
Prokaryotic
Eukaryotic
4
Q
What is a cell?
A
The smallest structural and functional unit of an organism
5
Q
What are all cells surrounded by?
A
A plasma membrane
6
Q
What are the three main ways cells can be connected?
A
Tight junctions
Anchoring junctions
Gap junctions
7
Q
What are the features of tight junctions?
A
They form fluid-tight seals which act as a barrier to fluid loss
They have limited permeability
They prevent molecules from passing through the intracellular space
8
Q
What is special about gap junctions?
A
They allow ions and small molecules to pass from cell to cell, to enable intercellular communication
9
Q
What is the cell cycle?
A
The cycle of events in eukaryotic cells from one cell division to the next
10
Q
What are the phases of the cell cycle?
A
Interphase
Mitosis
Cell division
11
Q
What can happen if a cell can no longer control mitosis normally?
A
Tumours may form
12
Q
What is a tissue?
A
A group of cells which all perform the same function
13
Q
What are the four types of bodily tissue?
A
Epithelium
Connective tissue
Muscle tissue
Nervous tissue
14
Q
What types of cells are there?
A
Epithelial Support (eg cartilage, bone) Adipose Contractile (smooth muscle, skeletal muscle) Nerve Gametes Blood Immune system cells Hormone-producing cells
15
Q
What does the morphology (structure, appearance) of a particular cell tell us?
A
Its specific function
16
Q
What are stem cells?
A
Cells which are able to divide, differentiate and replace specialised cells which are damaged/old
17
Q
What are the two types of stem cell?
A
Adult
Embryonic
18
Q
How are adult stem cells described and what does that definition mean?
A
As being multipotent, which means they can generate many tissue-specific cell types
19
Q
How are embryonic stem cells described and what does that definition mean?
A
Pluripotent, which means they can generate cells of any type in the body
20
Q
What is the difference between endothelial and epithelial cells?
A
Epithelial cells line both internal and external surfaces but endothelial cells line internal surfaces of components of the circulatory system
21
Q
What are endothelial cells?
A
Cells which line the interior surface of blood and lymphatic vessels
22
Q
What are epithelial cells and where are they found?
A
A type of cell which lines every surface of the body
Found on skin, blood vessels, urinary tract, organs
23
Q
What is an allele?
A
The dominant form of a given gene
24
Q
What is a genotype?
A
Genes which are responsible for a particular trait (eg eye colour)
25
What is a phenotype?
The physical expression of the genotype (eg blue eyes)
26
What is a karyotype?
An individual’s collection of chromosomes
27
What does autosomal mean?
A non sex-related chromosome
28
What is a nucleotide?
A building block of RNA/DNA
29
What are the components of a nucleotide?
Phosphate
Sugar (ribose/deoxyribose)
A base
30
What are the bases?
Adenine
Cystine
Guanine
Thymine (Uracil instead of thymine in RNA)
31
Which base is different in RNA?
Uracil replaces Thymine
32
What are amino acids?
Organic compounds which combine to form proteins and are vital for certain functions (eg protein synthesis, tissue repair)
33
Why are amino acids vital?
They are key to certain physiological functions such as protein synthesis and tissue repair
34
What is transcription?
The process which makes an RNA copy of a gene sequence
35
What is translation?
The process of creating proteins from an mRNA template
36
What is tRNA?
Temporary carriers of amino acids
37
What is a ribosome?
An organelle which is involved in protein synthesis
38
Where are ribosomes found?
Freely floating in cytoplasm, or attached to rough endoplasmic reticulum
39
What are the two main stages of cell division?
Interphase
| Mitotic phase
40
What does eukaryotic mean?
That the cell has a nucleus and membrane enclosed organelles
41
What is cellular respiration?
The process by which ATP is made
42
What is transcription and translation?
Transcription is the production of mRNA molecules from the DNA template
Translation is the production of encoded protein from the mRNA
43
What is a macromolecule? Give an example of one
A molecule containing a large number of atom
| Proteins, nucleic acids, synthetic polymers
44
What determines the folding and shape of a protein?
It’s amino acid sequence
45
What is the difference between prokaryotic and eukaryotic cells?
Eukaryotic cells contain a nucleus and a range of organelles
| Prokaryotic cells only have ribosomes
46
A plasma membrane surrounds which type/s of cells?
All cells
47
Are human cells prokaryotic or eukaryotic?
Eukaryotic
48
What can happen if a cell can no longer control mitosis normally?
Tumours can form
49
What are ribosomes?
| What do they do?
Organelles found in the cytosol
| Manufacture proteins
50
What is an organelle?
Part of the cell which performs a specific function (effectively a cell organ)
51
What is the nucleus?
The structure where ribosomes are made
52
What is the Golgi Apparatus?
| What does it do?
An organelle which processes and packages proteins and lipid molecules, especially proteins destined to be exported from the cell
It also builds lysosomes (cell digestion machines)
53
What are vesicles?
Membranous sacs which are usually involved with the transport and secretion of molecules
54
What are lysosomes?
| What do they do?
Specialised vesicles containing enzymes
| Their purpose is to digest things
55
What are mitochondria?
| What do they do?
The powerhouse of the cell
| They generate most of the chemical energy needed to power the cell's biochemical reactions
56
What is the endoplasmic reticulum?
| What does it do?
A network of membranes within the cytoplasm of the cell
SER acts as a storage organelle, important in the creation and storage of lipids and steroids
RER is important in the synthesis and packaging of proteins
57
Why is the rough endoplasmic reticulum (RER) rough?
Because it is studded with ribosomes
58
What is the rough endoplasmic reticulum's function?
It plays a central role in the synthesis of proteins
59
What is the smooth endoplasmic reticulum's function?
It is involved in the synthesis and storage of lipids
60
Where are ribosomes made?
In the nucleus
61
What is the lipid bilayer?
A membrane composed of phospholipid molecules
62
How is the lipid bilayer composed?
Two layers of phsopholipid molecules; the tails all point inwards and the heads outwards
63
Why do phospholipid heads point outwards?
They are hydrophilic
64
Why do phospholipid tails point inwards?
They are hydrophobic
65
What is an ion channel?
A specialised protein in the plasma membrane which provides a way for charged ions to cross it
66
What is the purpose of the plasma membrane?
To maintain the integrity of the cell
It also keeps the cytosol (internal fluid) and organelles (suspended objects) separate from the extracellular environment
67
What determines the fluidity of the plasma membrane?
The composition of lipids and how much cholesterol is present
68
What determines the permeability of the plasma membrane?
The types of proteins present
69
What happens in the G_0 phase of the cell cycle?
The cell is quiet at this point
70
What happens in the G_1 phase of the cell cycle?
The cell synthesises mRNA and proteins in preparation for mitosis
71
What happens in the S phase of the cell cycle?
DNA is replicated and two complete copies are produced
72
What happens in the G_2 phase of the cell cycle?
The new cell is checked to ensure it is not defective
Organelles multiply
Extra protein is synthesised
Materials (eg lipids) for the membrane may be produced
73
What happens in the M phase of the cell cycle?
The cell divides into two daughter cells
74
What does amphipathic mean?
To have dual polarity
75
How do CO2 and small molecules cross the plasma membrane?
By diffusion
76
How do ions or larger molecules cross the plasma membrane?
Proteins facilitate them crossing as they are too large for diffusion
77
What are the two main qualities of the plasma membrane?
Fluidity
| Permeability
78
How does primary active transport work?
Chemical energy (eg ATP) is used to move molecules over a membrane against their gradient
79
What is secondary transport?
Transport via the concentration gradient that is created by primary active transport
80
What is meant by the term "simple diffusion"?
Passive diffusion of ions/molecules via specific proteins (channels, carriers, transporters)
81
What do symporters do?
Transport molecules/ions across the phospholipid membrane in the same direction as the concentration gradient
82
What do antiporters do?
Transport molecules/ions across the phospholipid membrane in the opposite direction to the concentration gradient
83
What is cytoplasm composed of?
Cytosol (fluid within the cell)
| Cell organelles
84
What is exocytosis?
The process of moving materials from within a cell to the exterior of a cell
85
What is endocytosis?
The process of moving materials from outside a cell to within it
86
Aside from proteins, what other substances are exported out of a cell by exocytosis?
Waste products
87
What is meant by the term "facilitated diffusion"?
The passive transport of molecules or ions across the plasma membrane, via specific proteins (channels, carriers, receptors)
88
What are the two reasons solutes are able to diffuse across the plasma membrane?
A concentration gradient exists across the membrane
| The solute can pass freely across the membrane
89
What is a concentration gradient?
A process which is used for moving particles from an area of higher concentration in a solution to an area of lower concentration
90
Why are concentration gradients important?
They allow for the movement of solutes and gases by diffusion
91
Is ATP required in the process of simple diffusion?
No
92
What is ion channel diffusion?
Transport across cell membranes which occurs due to ion channels within the membrane
93
What is carrier-mediated diffusion?
Diffusion across the plasma membrane which is facilitated by carrier proteins such as glucose
94
Roughly how much of a cell's energy is spent in maintaining a concentration gradient across the plasma membrane?
About 45%
95
What is the sodium-potassium pump?
A specialised type of transport protein which is found in the cell membrane
96
What are the ratios of sodium and potassium which are transported by the sodium-potassium pump?
3 sodium ions out for every 2 potassium ions brought in
97
What is the purpose of the sodium-potassium pump?
It underlies most of our cellular processes
98
What powers the sodium-potassium pump?
ATP
99
How does the sodium-potassium pump work?
Sodium ions bind to the pump
A phosphate group from ATP attaches to it, causing it to change shape
The pump then releases 3 sodium ions
It binds to 2 potassium ions
The phosphate group detaches, causing the pump to release the 2 potassium ions into the cytoplasm
100
What is the alternative name for the sodium-potassium pump?
Sodium-potassium ATPase
101
The sodium-potassium pump is an example of which type of cellular transport?
Primary active transport
102
How do carrier mediated proteins work?
They change shape to faciliate diffusion of solutes across the cell membrane
103
What is ATP composed of?
Ribose (a pentose sugar)
Adenine (nitrogenous base)
Three phosphate groups
104
What are the products of ATP being broken down?
ADP (adenosine diphosphate)
| A single phosphate group
105
What is phosphorylation?
The process of adding a single phosphate group to an existing molecule in order to prepare it to change or do work (eg the addition of phosphate to ADP in order to form ATP)
106
Where in the body might you find epithelial cells?
The lining of the digestive tract and blood vessels
| The outer layer of skin
107
Give some examples of places in the body you might find support cells
Fibrous support tissue
Cartilage
Bone
108
Where in the body might you find adipose cells?
Under the skin
| Around organs
109
Where in the body might you find contractile (muscle) cells?
Skeletal muscle
Heart muscle
Smooth muscle
110
Where in the body might you find neurons?
Brain
| Spinal cords
111
Where in the body might you find gametes?
Eggs/sperm
112
Where in the body might you find blood cells?
Circulating red and white cells
113
Where in the body might you find immune system cells?
Lympoid tissues (lymph nodes, spleen)
114
Where in the body might you find hormone-producing cells?
Thyroid/adrenal glands
| Pancreas
115
What are the properties of (cellular) tight junctions?
They form a fluid-tight seal, enabling entire sheets of cells to join together
This acts as a barrier to fluid loss
116
What are the properties of (cellular) anchoring junctions?
They join tissues subjected to stretching or friction
117
What are the properties of (cellular) gap junctions?
They bring cell membranes close together, meaning small molecules can pass directly from the cytosol of one cell into the cytosol of another cell
118
What must first happen to the genetic material contained in a cell before it can divide and form two new cells?
The chromosomes must be duplicated so that each new cell contains a full copy of the genome
119
What is meant by the term "somatic cell division"?
The type of cell division where daughter cells are identical to the parent cell
120
What is cytokinesis?
The part of the cell division process where the cytoplasm of a single eukaryotic cell divides and forms two daughter cells
121
In the human cell cycle, at what stage does cytokinesis (cytoplasmic division) occur?
During anaphase and continues through telophase
122
What is prophase?
| What occurs at this stage of the cell cycle?
The first stage of cellular replication
| The parent cell chromosomes condense, the nucleolus disappears, the mitotic spindle starts to form
123
What is metaphase?
| What occurs at this stage of the cell cycle?
The second stage of cell division
| The chromosomes align with the middle of the cell, ready to divide
124
What are the two main phases of the cell cycle?
Interphase
| Mitotic phase
125
What events occur during the S phase of cellular reproduction?
The DNA within the cell is replicated, producing two complete copies of the cell
126
What are the four main phases of mitosis?
Prophase
Metaphase
Anaphase
Telophase
127
For someone aged over 50, roughly how long does it take for the epidermis to renew itself?
Up to 84 days
128
What structures are you likely to find in the dermis layer of skin?
```
Sebaceous glands
Hair erector muscles
Sweat glands
Lymphatic vessels
Hair follicle
```
129
How are cells in different layers of skin distinguished from one another?
By the level of their content of keratin (increases toward the surface)
130
What are the two types of stem cells?
Adult
| Embryonic
131
Are adult stem cells multipotent or pluripotent?
Multipotent
132
What does multipotent mean (in reference to stem cells)?
Stem cells which are able to generate multiple, tissue-specific cell types
133
What does pluripotent mean (in reference to stem cells)?
Stem cells which are not limited to generating cell types of a particular tissue, but which can generate cells of any type within the body
134
What are induced pluripotent stem cells?
Stem cells which are generated in research laboratories using cells harvested from adults and that have been "reprogrammed" to become pluripotent
135
What is the epidermis?
The surface layer of the skin
