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Cells Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What are antigens

A

Proteins on the surface of cells that cause an immune response
Allows immune systems to recognise : pathogens , cells from organisms of the same species, abnormal body cells, toxins

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2
Q

Self antigens

A

On our own cells

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3
Q

Non- self

A

Foreign

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4
Q

What is a pathogen?

A

Organisms that cause disease, destroy host cells.

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5
Q

Cellular immune response

A

Phagocytosis and t-cells

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6
Q

Humoral response

A

B-cells and plasma cells

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7
Q

What is bacteria

A

Living cells that can multiply rapidly, attack tissues in host and release toxins

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8
Q

What are viruses

A

Burst out of host cell into bloodstream, difficult to treat without affecting the host

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9
Q

Phagocytosis:

A

First line of defence
Identifies the foreign antigen and engulfs it into the phagocytic vacuole.
Lysosomes fuse with the phagocytic vacuole which break the bacteria down.

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10
Q

Components of cell: red blood cell

A

Contains haemoglobin which carries oxygen around the body

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11
Q

Plasma

A

Contains salts, sugars and proteins. Distributes materials and hormones throughout the body. Also carries waste products

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12
Q

Platelets

A

Bits of dead cell to help clot the blood

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13
Q

White blood cell

A

Destroy invading microbes

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14
Q

Active immunity

A

When you make your own antibodies
Natural - produce antibodies + memory B cells
Artificial - vaccination
Slow, long term , make memory cells, exposed to antigen

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15
Q

Passive immunity

A

When you are given antibodies by another organism
Natural - mother to child
Artificial - given someone else’s antibodies (blood transfusion )
Fast, short term, dont make memory cells, no exposure to antigen

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16
Q

T-cells

A 
Made in the bone marrow 
Mature in the thymus 
Carry out cell mediated response 
Recognise and destroy abnormal cells 
Produce a protein that makes holes in the cells surface membrane 
TH cells active B cells 
TC kill pathogens
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17
Q

B-cells

A

Made in and mature in the bone marrow
Responsible for antibody production
B cell with the complimentary antibody forms antigen-antibody complex
Selected b cels divides and clones itself

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18
Q

Plasma cells

A

Clones of the selected B cell
Make monoclonal antibodies
Stick pathogens together = agglutination
When infections is over , plasma cells are saved as memory b cells

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19
Q

Lymphocytes

A

Have an englarged nucleus because they are producing lots of ribosomes|+mRNA. Produced in the bone marrow

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20
Q

Antibody

A

A molecule made by b lymphocytes in response to stimulation by the appropriate antigen
Also known as immunoglobins
Specific to a particular antigen
Usually a protein or glycoprotein

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21
Q

Structure of an antibody :

A

4 polypeptide chains held together by disulfide brides
A genetic constant region allowing antibodies to attach to phagocytic cells
Variable regions which is specific to a particular antigen this depends on amino acid sequence
Hinge region which allows the antigen to flex in order to bind to more than one antigen

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22
Q

Primary immune response

A

Slow- phagocytosis
Pathogen multiplies - feel symptoms
After the infection you save memory cells

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23
Q

Secondary immune response

A

Same pathogen infects you
Faster+stronger
No symptoms

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24
Q

What is the Elisa test

A

Test to see if patients have a specific antibody or antigen

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25
Q

Direct elisa test

A

Only one antibody used test for antigens

1) immobilised antipodes attached to a wall
2) sample added (e.g blood plasma )
3) if blood plasma companies antigen an antigen- antibody complex formed
4) rise to remove unbound antigens
5) antibody+ enzyme added
6) rinse
7) add substrate = if there’s a colour change it is a positive test

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26
Q

Indirect Elisa test

A

Uses two antibodies( a primary antibody and a secondary enzyme )

1) antigen is fixed to the well
2) sample is added - if complimentary an antigen-antibody complex formed
3) rinsed to remove unbound antibodies
4) different antibody added + enzyme
5) will only bind if 1st antibody is present
6) rinses to remove antibodies are unbound
7) substrate added = colour change

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27
Q

Vaccine

A

Contains antigens from a dead/weakened pathogen
Stimulates immune system to produce antibodies/plasma cells/ memory cells without causing illness
If infected post vaccine you undergo secondary response

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28
Q

Why don’t you feel ill from a vaccine

A

Because they contain an unactivated form of the pathogen killed by heat treatment

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29
Q

Herd immunity

A

The higher % that are vaccinated, the fewer people there are to pass on the disease

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30
Q

Antigenic variability

A

Antigens on the surface of pathogens change due to mutation
Antigen is no longer complimentary to the antibody
Infected again - primary response
Some pathogens may have strains - vaccines only work on some strains

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31
Q

The MMR controversy

A

1998- scientific paper speculated that the MMR vaccine causes autism
The vaccine could damage the bowel allowing the toxins cause autism in the brain
The authors did not prove that this was the case but still recommended that doctores stopped administering the MMR vaccine until more research was done

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32
Q

Virus reproduction

A

1) virus attachment proteins binds to receptor of the host (th cells)
2) reverse transcriptase makes double stranded DNA from RNA
3) DNA enters nucleus via nuclear pore
4) TH cells makes copies of virus, genetic material and protein
5) reforms capsid
6) leaves host cell taking on envelope from hosts membrane

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33
Q

What are monoclonal antibodies

A

Identical antibodies made from same B cell/ plasma cell

34
Q

Uses : targeting medication

A

Used to deliver drugs
Bind to only target cell
Attach drugs to antibodies

35
Q

Uses : medical diagnosis

A

1) monoclonal antibodies added to a plate
2) sample added - if antigen present it forms an antigen-antibody complex
3) rinsed to remove unbound antigens
4) same monoclonal antibody is added with an enzyme/ colour attached
5) rinsed again
6) observe for a marker - colour change

36
Q

Formation of monoclonal antibodies

A

1) antigen is injected into a mouse
2) the mouse naturally produces lymphocytes
3) spleen cell produce lymphocytes are removed
4) spleen cells are fused with cancerous white blood cell to form hybridoma cell
5) the hybridoma cells divide and produce millions of monoclonal antibodies specific to the original antigen.

37
Q

HIV

A

Human immunodeficiency virus
Infects t-helper cells so the immune system becomes weak and develops AIDS
Doesn’t kill you directly

38
Q

AIDS

A

Acquired immune deficiency syndrome

39
Q

Eukaryotic cell organelles :nucleus

A

Nucleus= where chromosomes are found, controls activities s

40
Q

Eukaryotic- RER

A

RER= usually attached to nucleus, covered in ribosomes, modifies and folds proteins

41
Q

Eukaryotic - SER

A

SER= not attached to the nucleus, modifies and folds proteins

42
Q

Eukaryotic - golgi apparutus

A

Golgi apparatus = modify and package proteins and lipids and put them in vesicles for transport. Make lysosomes

43
Q

Eukaryotic=lysosomes

A

Lysosomes = contain digestive enzymes, used to hydrolyse pathogens

44
Q

Eukaryotic - mitochondria

A

Mitochondria = make ATP, site of aerobic respiration.

45
Q

Eukaryotic - chloroplast

A

Grana is a stack of thykaloid, double membrane

Site of photosynthesis

46
Q

Eukaryotic - cell wall

A

Strong that protects the cell from changing shape

47
Q

Eukaryotic - vacuole

A

Contains sugar and salt ( cellulose ), keeps cell fugid

48
Q

Eukaryotic - ribosomes

A

Makes proteins, attached to RER, made of proteins and RNA

49
Q

Prokaryotic - plasmid

A

Small loop of dna
Can be passed between bacteria
Carry useful genes

50
Q

Prokaryotes - cell wall

A

Made of a glycoproteins

Strength = shape

51
Q

Prokaryotes - flagella

A

Rotates to move the cell

52
Q

Prokaryotes - small ribosomes

A

Makes proteins

53
Q

Prokaryotes- loop of dna

A

No nucleus , dna is free in the cytoplasm

54
Q

Prokaryotes- capsule

A

Slime layer, adds protection

55
Q

Prokaryotes - cell membrane

A

Controls what goes in and out

56
Q

Cell fractionation

A

1) break cells open -
Keep ice cold to prevent enzyme activity
Keep isotonic to prevent osmosis
Use buffer to keep pH same
2) filter solution - removes cell debris and whole cells
3) ultra centrifugatiom-
Spin the test tube , heaviest organelles compressed into a pellet at the bottom
Remaining liquid is poured off
Spin again
Repeat …

57
Q

Order of organelles in cell fractionation

A

Ribosomes at the top

Nuclei at the bottom then chloroplast then mitochondria

58
Q

Light microscope

A 
Easy to use
Cheap 
Colour image
Much lower magnigfication 
Can’t see small organelles - ribosomes
59
Q

Scanning electron microscope

A

Much better magnification + resolution than light
3D image
Don’t need a thin section
Can’t see internal structures s

60
Q

Transmission electron microscope

A 
Best magnification + resolution -shorter wavelength of light 
Internal structure 
Can’t see living cells 
Specimen needs to be in a vacuum 
Use thin slice
No colour
61
Q

Why do specimens have kept in a vacuum for an electron microscope

A

Electrons are absorbed by molecules in air , this would prevent the electrons reaching the specimen §

62
Q

Microscope calculation

A

Imagine size= actual x magnification

63
Q

What happens in Interphase

A

DNA replicates

Chromosomes are loosely coiled = chromatin

64
Q

What happens in prophase

A

Chromosomes condense
Nuclear membrane centrioles move to the poles
Two chromatids joined at the centrometre

65
Q

What happens in metaphase

A

Double chromosome line up at the equator , spindle fibres forms
Translocation of chromosomes

66
Q

What happens in anaphase

A

Centrometres spit

Chromatids are pulled to opposite poles

67
Q

What happens in telophase

A

Nuclear membrane reforms

Cytokinesis - cytoplasm divides

68
Q

Mitosis and cancer

A

= uncontrolled cell division
Mutation in the oncogene and proncogene that switch on and off the proces
Malignant, cancerous tumors may spread from their origin . They develop their own blood supply which can transport malignant cells to other sites in the body

69
Q

Structure of the cell surface membrane

A

=phospholipid belayer
Hydrophilic heads face outward
Hydrophobic tails face inwards
Phospholipids can slide over each other = fluid mosaic model

70
Q

Diffusing through the cell membrane

A

Small non polar molecules diffuse through

Large polar molecules cant diffuse through easily

71
Q

Cholesterol and the cell surface membrane

A

Cholesterol binds to hydrophobic tails, makes the membrane more rigid , for strength and support

72
Q

What is diffusion

A

Net movement of molecules from high to low concentration and is passive
Carries on till equilibrium is reached

73
Q

How does concentration gradient affect rate of diffusion

A

The steeper the concentration gradient the faster the rate of diffusion

74
Q

How does surface area affect rate of diffusion

A

Bigger surface area, faster rate of diffusion

75
Q

Ficks law

A

Rate of diffusion = surface area x concentration gradient / thickness of membrane

76
Q

What is facilitated diffusion

A

The passive movement of molecules across the cell membrane via a specific transmembrane protein
Has a slower rate
Carrier proteins = intrinsic globular proteins
Carrier proteins are specific for the molecules they transfer

77
Q

Active transport

A

Against the concentration gradient
Uses energy from atp
Via a carrier protein
Affected by temperature, enzyme availability and cellular glucose concentration

78
Q

Co transport

A

Via carrier protein
Moves 2 molecules at one
One goes down its concentration gradient and one going against

79
Q

Absorption of glucose

A

1) sodium ions are transported out of epithelial cells by a sodium-potassium pump into the blood. - this maintains a much higher concentration of sodium ions in the lumen of the intestine than inside the epithelial cells
2) sodium ions diffused into the epithelial cells down the concentration gradient through a co-transport protein. As they diffuse they carry either amino acid molecules or glucose molecules with them
3) the glucose/amino acid pass into the blood plasma by facilitated diffusion using another type of carrier.

80
Q

What is osmosis

A

The passage of water from a region of higher water potential to a region of lower water potential through a selectively permeable membrane.

81
Q

What is a solute

A

Any substance that is dissolved in a solvent

82
Q

Water potential

A

High water potential - high % of water molecules, low % of solute , hypotonic. Pure water has a high water potential when its next to a solute
Low water potential ‘ lower % of water molecules, high % solute , hypertonic
The more solute that is added, the lower its water potential

Biology (17 decks)

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