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Biology Alevel > Cells > Flashcards

Cells Flashcards

(68 cards)

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1
Q

Describe The Nuclear Envelope

A

Continuous Double membrane that surrounds the cell

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2
Q

Describe The Nucleoplasm

A

Makes up the bulk of nucleus and contains chromatin

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3
Q

What is the function of nuclear pores

A

Allow passage of ribosomes and messenger RNA

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4
Q

Describe the nucleolus

A

Dark centre within nucleoplasm it manufactures ribosomes

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5
Q

What are the Differences of smooth and rough endoplasmic reticulum

A

•Rough has ribosomes on and is involved in synthesis of protein
•Smooth synthesises carbohydrates and lipids

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6
Q

What are the similarities of smooth and rough endoplasmic reticulum

A

•Both consist of flattened sacks and tubules to increase surface area
•both are connected to the outer membrane of the nucleus

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7
Q

What are the structures of a mitochondria

A

•double membrane
•Cristae (folded inner membrane)
•Matrixm

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8
Q

Describe the mitrochondria cristae

A

Folded inner membrane needed to increase surface area for attachment of enzymes for respiration

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9
Q

Describe the mitochondria matrix

A

Makes up remainder of mitochondria and contains DNA ribosomes and enzymes for respiration

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10
Q

What are the structures of a chloroplast

A

•Chloroplast envelope (double membrane)
•thylakoids and grana
•lamella
•Stroma

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11
Q

Describe the thylakoid

A

Folded membranes containing chlorophyll pigment

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12
Q

Describe the grana

A

Stack of multiple thylakoids attached by lamella

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13
Q

Describe the stroma

A

Fluid filled matrix containing ribosomes to make enzymes for photosynthesis

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14
Q

Describe the Golgi apparatus’s job

A

Modifies, sorts, and packages proteins and lipids for secretion or delivery to other parts of the cell

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15
Q

What happen to proteins, carbohydrates and lipids in the Golgi body

A

Carbohydrates can be added and lipids and proteins are labelled them and forms vesicles and leave the cell

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16
Q

What are differences of transmission electron microscopes and scanning electron microscope

A

•scanning has a 3d image where cells are coated in a metal, no dissection needed
•Transmission has 2d image where cells are stained with Metal it has a higher resolution but cells need to be dissected

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17
Q

What are the steps of cell fractionation

A

Homogenisation.—>filtration—> Differential centrifugal

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18
Q

Negatives of transmission electron microscopes

A

Difficult to prepare the slide as needs to be cut thin for electrons to pass through, cells will be dead as it’s in a vacuum in black and white it’s also expensive

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19
Q

What are the steps to cell fractionation

A

Homogenisation—>filtration—>differential centrifugation

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20
Q

Describe the buffer solution used before cell fractionation

A

Is cold to prevent enzyme denaturing and slow down metabolic processes
•it has the same water potential as the cell to prevent it bursting

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21
Q

What happens during differential centrifugation

A

Cellular components are separated off by spinning samples at various speeds larger particles settle to bottom of tube first followed by lighter as speed increases

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22
Q

What is the order of the mitosis

A

Prophase—>Metaphase—> Anaphase —>Telophase

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23
Q

What happens during prophase

A

•Chromatin condense and form chromosome
•centrioles begin to form spindle fibres
• nuclear envelope breaks down

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24
Q

What happens during metaphase

A

Chromosome align along equatorial plate
Spindle fibres attach

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25
What happens during Anaphase
Chromosomes pulled apart by spindle fibres to opposite poles
26
What happens during Telophase
Chromosomes decondense and nuclear envelope reforms
27
What happens during Interphase
Replication of genetic material and organelle
28
What happens during cytokinesis
Cell divides into two daughter cells
29
What is the function of a plasmid
Is a loop that Can replicate independently and carry’s advantageous DNA that can be transferred between bacteria such as antibiotic resistance
30
Why is a stain used in microscopy
To enhance contrast between different structures
31
Define facilitated diffusion
Net movement of particles down concentration gradient through a channel or carrier protein
32
What is the limiting factor of facilitated diffusion ?
Number of channel/carrier proteins
33
What molecules can diffuse through the cell membrane ?
•none polar molecules such as oxygen •water due to its size
34
What is the vacuole Membrane made of?
Tonoplast
35
Why do cells have a membrane ?
•Controls what enters and leaves •increase surface area •Creates separate environments •Cell signalling-receptors for hormones •structural support
36
What do integral proteins do?
Allow for large molecules to enter the cell
37
What is the difference between integral and periferal proteins ?
Integral-all the way through membrane Periferal-partially through membrane
38
Describe the phospholipid bilayer
•Double layer of phospholipids with hydrophobic heads in outside •It allows movement of non polar and small molecules through cell
39
What are peripheral proteins ?
Act as antigens for cell signalling And allow cells to connect
40
What are carrier proteins ?
•Allow movement of polar or large molecules into the cell •contain binding sight
41
What does cholesterol in cell Membrane do?
Reduce rigidity at low temp Reduce fluidity at high temp Reduce water loss
42
Define osmosis
Net movement of water from low water concentration to a high water concentration across a partially permutable membrane
43
Define hypertonic
Had a higher solute concentration
44
Define isotonic
Equal solute concentration
45
Define hypotonic
Lower solute concentration
46
What happens to a plant cell placed in a hypertonic solution
The vacuole will shrink and cell membrane pulls away from the cell wall -plasmolysis
47
Define water potential
Likelihood water molecules will diffuse in or out of a solution
48
Define active transport
Movement of molecules or ions into out out of a cell from an area of low concentration to an area of a higher concentration using ATP
49
Why use Active transport ?
•movement of particles against concentration gradient • set up a concentration gradient
50
What is ATP and how does it work?
•Is a currency of energy •has three phosphate groups removing one releases energy
51
Define co-transport
Form of active transport where two molecules move across a cell membrane together one moves down its concentration gradient allowing for the other to be pulled against its concentration gradient
52
Define endocytosis
Active transport that moves particles into a cell by enclosing them in a vesicle made from cell membrane
53
Define exocytosis
Active transport that moves particles out of a cell, the vehicle fuses with the plasma membrane
54
Define a pathogen
Microorganism which causes an imbue response
55
Define antigen
Protein molecule in a cell surface membrane that triggers an immune response by lymphocytes
56
Define memory B lymphocyte
They remember which B-Cell creates the right antibody and stay in your blood stream for decades
57
Define plasma B lymphocyte
Create the antibodies straight away are destroyed after use
58
What is the cytotoxic T-Cell
Releases protein perforin perforating the cell membrane of pathogen
59
What is the helper T-Cell
Activates other T and B Cells
60
What is the suppressor T-Cell
Controls your immune system preventing lymphocytes attacking your own cells
61
What is the memory T-Cell
Remember the shape of antigen providing long term immunity
62
What happens to a pathogen after it is engulfed and digested by a phagocyte
Antigens are presented on the outside of the cell where a Helper T-Cell takes and activates the B-cells with the desired antigen shape which is known by the memory T-Cell the Plasma B-cells then produce the antibodies known by the memory B-cells and will kill the pathogen
63
Why use a ELISA test?
Find out out if one has antigens for a pathogen and quantity of antigens
64
Difference between direct and indirect targeted therapy
MAB block receptor that would enable uncontrolled growth - direct MAB has cytoxic/radioactive drug attached - indirect
65
Difference between direct and indirect ELISA test
Direct uses one antibody Indirect uses two antibodies
66
Define passive immunity
Introducing antibodies from and outside source with no exposure to a pathogen
67
Define active immunity
Stimulating production of antibodies from an individuals own immune system
68
Define lipase
Enzymes that hydrolyse the ester bonds of lipids to form fatty acids and mono-glycerides

Biology Alevel (8 decks)

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