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Cells Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Structure and function of nucleus

A
  • double membrane nuclear envelope
  • small holes called nuclear pores for material like ribosomes to get out
  • granular jelly like material called nucleoplasm
    small sphere inside called nucleolus where rRNA is produced and makes ribosomes
    Function - site of dna relocation and transcription, contains genetic code for each cell
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2
Q

structure and function of endoplasmic reticulum

A

Structure:
RER and SER have both folded membrane called cristae
RER associated w ribosomes
Function:
RER : protein synthesis
SER : synthesis and store lipids and carbohydrates

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3
Q

structure and function of golgi apparatus

A

Structure
- folded membranes
- secretary vesicles transport substances out of cell
- microvilli increase surface area for absorption
function - modify, package and transport substances
- form lysosomes
- add carbohydrates to proteins to form glycoproteins

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4
Q

structure and function of lysosomes

A

structure
- bags of digestive enzymes, can contain 50 different enzymes
function
- hydrolyse phagocytic cells
- digest worn out organelles for reuse of materials
- exocytosis: release enzymes to outside of cell to destroy material

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5
Q

structure and function of mitochondria

A 
structure
- double membrane
- inner membrane called cristae
- fluid centre called matrix
- loop of mitochondria dna
function
- site of aerobic respiration
- site of ATP production
- DNA to code for enzymes needed in respiration
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6
Q

structure and function of ribosomes

A

structure
- small, made up of two subunits of protein and rRNA
- 80s in eukaryotic
- 70s in prokaryotic, mitochondria and chloroplasts
function
- site of protein synthesis

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7
Q

structure and function of vacuole

A

structure
- filled with fluid surrounded by single membrane called tonoplast
function
- makes cells turgid for support
- temporarily stores sugars and amino acids

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8
Q

structure and function of chloroplasts

A
  • double membrane
  • stacks of folded membranes called thylakoids
  • fluid filled storms contains enzymes for photosynthesis
    function
  • site of photosynthesis
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9
Q

structure and function of cell wall

A

structure :
plants - made of microfibrils and cellulose polymer
fungi - made of chitin, a nitrogen containing polysaccharide
function
- provides structural strength and rigidity to the cell
- prevents cell bursting or shrinking

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10
Q

structure and function of plasma membrane

A

structure
phospholipid bilayer - molecules embed within and attached in the outside
function
controls entrance and exit of molecules

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11
Q

compare prokaryotic and eukaryotic cells

A 
prokaryotic smaller
prokaryotic no membrane bound organelles
prokaryotic 70s eukaryotic 80s
prokaryotic no nucleus
prokaryotic meurin cell wall
eukaryotic no vacuole
eukaryotic may contain plasmids capsule flagella
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12
Q

what are viruses

A

Acellular and non living, they relocate inside of cells making it difficult to destroy them without harming the host cell

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13
Q

what are the types of microscopes

A

optical (light) , transmission electron, scanning electron

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14
Q

what is magnification?

A

how many times larger an image is compared to the object

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15
Q

what is resolution

A

the ability to distinguish between two separate objects

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16
Q

compare optical microscope with electron microscopes

A

optical use beam of light where electron uses beam of electrons to make image
electrons use electromagnets to condense beam
optical have a longer wavelength so poor resolution
electron have shorter wavelength so higher resolution
optical colour electron bw
optical can view living samples
electron samples must be in a vacuum thus dead

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17
Q

compare SEM and TEM

A 
SEM electrons bounce off surface of specimen where TEM electrons pass through specimen
SEM 3D TEM 2D
Both use magnets not lenses
both produces electromicrograph 
both produce BW image
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18
Q

how to calculate magnification

A

image size/ actual size

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19
Q

process of cell fractionation and ultracentrifugation

A
  1. cells homogenised in a pestle and mortar.
    ice cold to limit enzyme activity
    buffeted to prevent enzymes denaturing
    isotonic to maintain same water potential in and out of cell to prevent shrivelling or burst
  2. filter to remove complete cells or large debris, leaving suspension or cells
  3. homogenate put in test tubes in centrifuge and spun at low speed. most dense organelles will collect at the bottom of tube forming a pellet. liquid is called supernatant
    spin at a faster speed for longer and keep repeating until all is left is ice cold solution
    order : nuclei, chloroplast, mitochondria, lysosomes, ER, ribosomes
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20
Q

why don’t viruses undergo cell division

A

non livint

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21
Q

what happens during interphase

A

chromosomes extended and not visible, cell bust making proteins. chromosomes replicate and nucleolus is visible

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22
Q

what happens during prophase

A

chromosomes condense, nucleolus disappears and spindle apparatus made of spindle fibres form

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23
Q

what happens during metaphase

A

nuclear membrane breaks down, chromosomes align at the equator of the cell. each chromosome is attached to spindle fibres by centromeres

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24
Q

what happens during anaphase

A

centromeres divide and spindle fibres pull individual chromatids taking the chromosome apart

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25
Q

what happens during telophase

A

chromosomes reach respective polar ends and become longer and thinner. spindle fibres disintegrate and nucleolus forms

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26
Q

what happens during cytokinesis

A

single eukaryotic cell divide into two diploid daughter cells which are identical to parent cell

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27
Q

how to calculate mitotic index

A

(number of cells in mitosis/ total number of cells) *100

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28
Q

what is a protoroncogene

A

genre that produce proteins that stimulate cell division and ihibit cell death.

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29
Q

what can be said about oncogenes

A

hey can’t be controlled by suppressors and thus keep stimulating cell division resulting in a tumour

30
Q

describe the process of binary fission

A
  1. circular dna of bacterium is replicated
  2. undergoes cytokinesis, cytoplasm divided forming two new cells that are genetically identical
  3. each daughter cell contains single copy of circular dna
31
Q

describe the fluid mosaic model

A

mixture and movement of proteins, glycoproteins and cholesterol arranged within a phospholipid bilayer consisting of hydrophilic heads and hydrophobic tails. can be described as a partially permeable membrane as only lipid soluble substances and very small molecules can pass through.

32
Q

what are channel proteins

A

hydrophilic pores that allow select ions such as Ca, K that travel in water into and out of cell

33
Q

what are carrier proteins

A

proteins that allow substances to pass through via facilitated diffusion. they act as carriers for active transport and as receptor sites for hormones

34
Q

what is diffusion

A

net movement of particles from an area of high to low concentration due to the random movement of particles. passive process meaning atp is not required (no energy needed) molecules must be lipid soluble and small to diffuse across membranes

35
Q

what is facilitated diffusion

A

movement of particles from area of high to low concentration using a channel or carrier protein.

  • channel proteins form tubes filled with water allowing water soluble ions to pass though
  • carrier proteins bind with a molecule such as glucose causing a change in the shape of the protein, enabling the molecule to be released to the other side of the membrane
36
Q

what is osmosis

A

movement of water from areas of high to low WP across a partially permeable membrane

37
Q

what is water potential

A

pressure created by molecules measured in kPa

38
Q

what is meant by isotonic

A

WP is the same in solution and cell within solution

39
Q

what is meant by hypotonic

A

WP of solution is more positive that that it the cell. more water moving in by osmosis, risking cell bursting

40
Q

what is meant by hypertonic

A

WP it if solution is more negative than that of cell. more water moving out by osmosis causing cell to shrivel

41
Q

what is active transport

A

movement of substances from low to high concentration using metabolic energy and a carrier protein

42
Q

describe process of cotransport

A
  1. sodium ions leave epithelial cell and enter blood via active transport using carrier protein
  2. sodium concentration in cell is lower in the lumen
  3. sodium ions enter by facilitated diffusion
  4. glucose absorbed with sodium ions against concentration gradient
43
Q

what is a lymphocyte

A

cells that identify the presence of pathogens and potentially harmful foreign substances in the body and destroy it neutralise them to prevent harm

44
Q

how can lymphocytes identify and remove foreign substances

A

they can distinguish between pathogens and self cells due to the molecules on its surface, usually proteins as their tertiary structure enable lots of unique identifiable shapes to be made

45
Q

what can lymphocytes identify

A

pathogens eg bacteria
cells from other organisms or same species
abnormal body cells eg cancer cells
toxins eg cholera

46
Q

what are antigens

A

molecules that generate an immune response by lymphocyte cells when detente’s in the body. usually found on surface of crlls

47
Q

what adaptations do cells have for rapid transport

A

increased SA

increased number of protein channels and carrier molecules in membranes

48
Q

what is meant by antigen variability

A

mutations of pathogens occurring in a gene that codes for the antigen will cause the shape of the antigen to change. this means previous immunity is no longer effective as memory cells will only have information of the old antigen shape

49
Q

describe process of phagocytosis

A
  1. phagocyte recognises antigens on pathogen
  2. phagocyte engulfs pathogen
  3. pathogen contained in the vacuole or vesicle in cytoplasm of her he phagocyte
  4. lysosome fuses with phagocytic vacuole and release hydrolytic enzymes to break down pathogen
  5. phagocyte presents pathogens antigens on its surface to activate other immune system cells
50
Q

what are antigen presenting cells

A

infected body cells that present viral antigens on their surface

51
Q

describe the cell mediated response

A
  1. complimentary tH lymphocytes bond to foreign antigen on antigen presenting cell
  2. cytokines released which stimulate:
    a. clonal expansion of complementary t cells which become memory cells or trigger humoral response.
    b. clonal expansion of cytotoxic cells which secrete enzyme preform to destroy infected cells
52
Q

describe what happens in the humoral response

A

B cell takes in antigen by endocytosis
1. complimentary tH lymphocytes bind to foreign antigen on APC
2. cytokines released that stimulate clonal expansion of complementary B lymphocytes
3. B cells differentiate to plasma cells
4. Plasma cells secrete antibodies with a complementary variable region to antigen
B memory cells can divide into plasma cells when reinfected with the same pathogen to make large numbers of antibodies rapidly

53
Q

features memory B cells

A

live for decades in the body where plasma cells are short lived
divide by mitosis and make plasma cells rapidly if they collide with antigens theyve previously encountered
this means large numbers of antibodies can be produced so rapidly jay the pathogen is destroyed before any symptoms can happen

54
Q

what is agglutination

A

antibodies are flexible and bind to multiple antigens to clump them together. makes it easier for phagocytes to locate and destroy pathogens

55
Q

what is passive immunity

A

antibodies introduced into the body but the pathogen doesn’t enter the body, meaning plasma and memory cells aren’t made. thus no long term immunity. e.g. antibodies passed from breast milk to baby

56
Q

what is active immunity

A

immunity created by one’s own immune system following the exposure of a pathogen or its antigen

57
Q

what is natural active immunity

A

following infection and the creation of the body’s own antibodies and memory cells

58
Q

what is artificial active immunity

A

following the introduction of a weakened version of the pathogen or pathogens through a vaccine

59
Q

state process of vaccination

A
  1. small amounts of weakened or dead pathogen or antigens introduced in mouth or via injection
  2. exposure to antigens activate B cell to go through clonal selection
  3. B cells undergo mitosis and make large number of cells that differentiate into plasma or memory B cells
  4. B cells make antibodies
  5. B memory cells divide rapidly when reinjected with same pathogen to make large numbers of antibodies rapidly
60
Q

what is here immunity

A

if enough of the population are vaccinated the pathogen can’t spread easily amongst it. this provides protection to those who aren’t vaccinated e.g. those too ill to get a vaccine, with lowered immunity or those too young

61
Q

describe structure of HIV

A
  • RNA and enzyme reverse transcriptase needed for viral replication
  • capsid outer fist
  • envelope made of membrane taken from host cells
  • protein attachments allowing virus to attach to hosts tH cell
62
Q

describe replication of HIV in tH cells

A
  1. HIV transported in blood until it’s attached to CD4 protein in tH cells
  2. HIV protein capsule fuses with tH cell membrane enabling RNA and reverse transcriptase to enter
  3. Reverse transcriptase copies viral RNA into DNA and movies to tH nucleus. this is why it’s called a retrovirus
  4. mRNA transcribed and tH cells start to create viral proteins to make new viral proteins
63
Q

what is aids and what does it result in the body

A

Aids is when replicating viruses by tH cells interfere with the functioning of the immune system
With tH being destroyed the host can’t produce an adequate immune response for other pathogens and left vulnerable to infections and cancer

64
Q

what is a monoclonal antibody

A

a single type of antibody that can be isolated and cloned

65
Q

what is an antibody

A

proteins are out binding sites complimentary in shape to certain antigens

66
Q

what are monoclonal antibodies used for

A

medical treatment
medical diagnosis
pregnancy tests

67
Q

what is direct monoclonal antibody therapy

A

monoclonal antibodies prevent cancer cells growing by preventing chemicals binding to cancer antigens which enable uncontrolled cell division. they are only designed to attach to cancer cells as it is complementary to antigens on cancer cells

68
Q

what is indirect monoclonal antibody therapy

A

monoclonal antibodies have a drug attached to them, so when they bind to complementary antigens on cancer cells the drug is taken to the cancer cells and kills them. reduces side effects that chemotherapy and radiotherapy use

69
Q

what can monoclonal antibodies he used to test for

A

pregnancy, influenza, hepatitis, chlamydia, prostate cancer

70
Q

describe process of ELISA test

A
  1. HIV antigens are on surface of well place
  2. blood from test user placed on test site
  3. HIV antibodies attach. rinse with water to rid of any other present antibodies
  4. second antibody with enzyme attached. rinse to get rid of any unbound enzyme antibodies
  5. colourless substrate added. if positive, substrate digested with enzyme colour changes
71
Q

ethical issues for monoclonal antibody production

A
  • uses mice to create MAB and tumour cells, leads to debates whether animal use to enable better treatments and detection of disease for humans is justifiable

Biology (6 decks)

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