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Cells Flashcards

(60 cards)

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1
Q

What is the function of the nucleus?

A

contains the hereditary material and regulates cell activities

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2
Q

What is the function of the nuclear envelope?

A

a double membrane that surrounds the nucleus controlling the movement of genetic material

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3
Q

What is the function of nuclear pores?

A

allows passage of large molecules

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4
Q

What is the nucleoplasm?

A

granular jelly-like material that suspends the nucleus bound structures

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5
Q

What are chromosomes?

A

protein-bound linear DNA

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6
Q

What is a chromatin?

A

a specific section of a chromosome

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7
Q

What are histones?

A

proteins

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8
Q

What is the nucleolus?

A

it manufactures ribosomal RNA and assembles the ribosomes

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9
Q

What is the mitochondria?

A

produces ATP through aerobic respiration

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10
Q

What is the function of the double membrane? (mitochondria)

A

outer- controls entry and exit of material
inner- folded to form cristae

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11
Q

What is the cristae? (mitochondria)

A

inner membrane extensions increasing the surface area for enzymes and proteins

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12
Q

What is the matrix? (mitochondria)

A

remainder of the mitochondrion containing proteins, lipids, ribosomes and DNA

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13
Q

What is the chloroplast?

A

disc shaped organelle that carries out photosynthesis

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14
Q

What is the function of the envelope (chloroplast)

A

selectively permeable double plasma membrane surrounding the organelle

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15
Q

What is the function of the grana? (chloroplast)

A

stacks of thylakoids containing chlorophyll and first stage of photosynthesis occurs here

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16
Q

What is the function of the stroma? (chloroplast)

A

fluid filled matrix where the second stage of photosynthesis occurs

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17
Q

What is the endoplasmic reticulum?

A

sheet like membranes spreading throughout the cytoplasm enclosing a network of tubules and flattened sacs called cisternae

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18
Q

What is the function of the rough endoplasmic reticulum?

A

large surface area for ribosomal synthesis of proteins and glycoproteins- provides a pathway for protein transport

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19
Q

What is the function of the smooth endoplasmic reticulum?

A

lacks ribosomes and is tubular in appearance- synthesis, storage and transport of lipids and carbohydrates

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20
Q

What is the function of the Golgi apparatus?

A

a stack of flattened sacs with vesicles- proteins and lipids produced by the endoplasmic reticulum are modified here

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21
Q

What are lysosomes?

A

isolate the enzymes from the rest of the cell before releasing them outside or into a phagocytic vesicle

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22
Q

What is the function of cellulose in the cell wall?

A

microfibrils provide considerable strength

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23
Q

What is the difference between the structure of fungi and algae?

A

algae- cellulose and glycoproteins

fungi- no cellulose, polysaccharide chitin and glycan as glycoproteins

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24
Q

What is the vacuole?

A

contains a solution of mineral salts, sugars, amino acids, wastes and anthocyanins

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25
What are the uses of the vacuole?
-turgidity to herbaceous plants -food store -attraction for pollination
26
What organelles are in a prokaryotic cell?
-plasma membrane -cell wall -capsule -cytoplasm -cilia -nucleoid -ribosomes -plasmid -flagellum
27
Describe the structure of a prokaryotic cell wall
-made from peptidoglycan (murein) -it is a complex polymer formed from amino acids and sugars
28
What are the three stages of the cell cycle?
interphase, cell division, cytokinesis
29
What happens during interphase?
cell grows and organelles divide, dna is duplicated and more proteins and organelles are made
30
What happens during cell division?
nucleus divides into two (mitosis) or four (meiosis)
31
What happens during cytokinesis?
cytoplasm divides to produce two (mitosis) or four (meiosis) daughter cells
32
Describe the process of mitosis
prophase- the chromosomes become visible and the nuclear envelope disappears metaphase- the chromosomes arrange themselves at the centre of the cell anaphase- each of the two threads of of a chromosome migrates to an opposite pole telophase- the nuclear envelope reforms
33
Describe the process of binary fission
- circular DNA and plasmids replicate and both copies attach to the cell membrane - cell membrane begins to grow between the two molecules of DNA dividing the cell into two genetically identical daughter cells - a new cell wall forms
34
What is a virus?
an acellular non-living particle
35
Describe the structure of viruses
they contain nucleic acids enclosed within a capsid and divide inside a living host cell, some viruses also have a lipid envelope
36
Do viruses go through cell division?
no, instead they attach to proteins on a cell's surface, inject their nucleic acid which provides instructions for the cell
37
What is the function of the cell surface membrane?
it allows different conditions to be established inside and outside a cell and controls the movement of substances in and out
38
What is the name of the structure of molecules in a cell-surface membrane?
fluid mosaic model
39
What is the fluid mosaic?
'fluid' refers to the molecules moving relatively to eachother 'mosaic' refers to each of the different molecules in the membrane
40
What are the components of the plasma membrane?
phospholipids, proteins, carbohydrates
41
What are the uses of cholesterol?
- reduces fluidity - less permeable to small water-soluble molecules - separates tails to prevent crystallisation - helps anchor peripheral proteins - helps with temperature changes - prevents leakage at high temperatures
42
What happens when a chemical binds to a carrier protein?
the protein changes shape
43
What is the function of a channel protein?
water filled- allows water-soluble ions/small substances
44
What is the use of a peripheral protein?
mechanical support
45
What is the definition of a passive process?
the energy required comes from the natural motion of particles rather than an external source
46
What is the definition of an active process?
the energy required comes from an external source such as ATP
47
define a specific defence mechanism
the response is immediate and for all pathogens
48
define a non-specific defence mechanism
response is slower and specific to each pathogen
49
what are some examples of specific defence mechanisms
-physical barrier - phagocytosis
50
what are some examples of non specific defence examples
-cell mediated (T lymphocytes) - humoral response (B lymphocytes)
51
what is an antigen?
proteins present on the cell surface membrane that trigger an immune response
52
where do b lymphocytes mature
in the bone marrow
53
what defence mechanism do b lymphocytes associate with
humoral immunity
54
where do t lymphocytes mature
in the thymus
55
what defence mechanism are t lymphocytes associated with
cell mediated immunity
56
what are antigen presenting cells (+examples)
cells that activate T-cells using the antigen from the pathogen - phagocytes - infected body cells - cancer cells - foreign cells
57
explain cell-mediated immunity
- pathogens invade body cells or are taken in by phagocytosis - the phagocyte presents antigens from the pathogen on its cell surface membrane - receptors on a specific helper T-cell fit exactly onto these antigens - the attachment activated the T cell to divide rapidly by mitosis and form clones - the cloned T-cells develop into memory cells and stimulate B-cells, phagocytes and activate cytotoxic T cells - cytotoxic T cells kill abnormal cells by making holes in the membrane with a protein called perforin - as a result the membrane is more permeable and will eventually die
58
define humoral immunity
involves the production of antibodies which are soluble in the blood and interstitial fluids (humour)
59
what is antigenic variation
when an antigen enters the humour, there will be one B cell that has an antibody on its surface that is complimentary
60
explain humoral immunity
- the surface antigens of an invading pathogen are taken up by a B-cell - the B cell processes the antigens and presents them on its cell surface membrane - helper T cells attached to the processed antigens on the B cell, activating it - the activated B cell divides by mitosis to create clones that all produce the same antibody - one clone known as the plasma cells secrete the specific antibody that exactly fits the antigen on the pathogens surface - the antibody attaches to the antigens on the pathogen to destroy them - the other clones of the B cells develop into memory cells. these respond to future infections and can produce plasma cells and subsequent antibodies more rapidly

Biology (8 decks)

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