TOPIC 2: CELLS Flashcards

Question

Cell vacuole function

Answer 1

Makes cells turgid - structural support temporary store of sugars, amino acids coloured pigments attract pollinators

Answer 2

Bind with a molecule, e.g. glucose, which causes a change in the shape of the protein this change in shape enables the molecule to be released to the other side of the membrane

Answer 3

Tubes filled with water enabling water-soluble ions to pass through the membrane selective channel proteins only open in the presence of certain ions when they bind to the protein

Answer 4

Non living and acellular contain genetic material, capsid and attachment proteins some (HIV) contain a lipid envelope + enzymes (reverse transcriptase)

Answer 5

Optical (light) microscopes Scanning electron microscopes (SEM) Transmission electron microscopes (TEM)

Answer 6

How many times larger the image is compared to the object calculated by equation: MAGNIFICATION=IMAGE SIZE/ACTUAL SIZE

Answer 7

The minimum distance between two objects in which they can still be viewed as separate determined by wavelength of light (for optical microscopes) or electrons (for electron microcopes)

Answer 8

Beam of light used to create image glass lens used for focusing 2D coloured image produced

Answer 9

Poorer resolution as long wavelength of light - small organelles not visible lower magnification can view living samples simple staining method vaccum not required

Answer 10

Beam of electrons passes through the sample used to create an image focused using electromagnets 2D, black & white image produced can see internal ultrastructure of cell structures absorb electrons and appear dark

Answer 11

Highest resolving power high magnification extremely thin specimens required complex staining method specimen must be dead vaccum required

Answer 12

Beam of electrons pass across sample used to create image focused using electromagnets 3D, black and white image produced electrons scattered across specimen producing image

Answer 13

High resolving power high magnification thick specimens usable complex staining method specimen must be dead vaccum required

Answer 14

Calibration of the eyepiece is required each time the objective lens is changed calibrate to work out the distance between each division at that magnification Break

Answer 15

Break open cells & remove cell debris so organelles can be studied

Answer 16

Process by which cells are broken open so organelles are free to be separated done using homogeniser (blender)

Answer 17

Cold reduces enzyme activity preventing organelle digestion Isotonic prevents movement of water by osmosis - no bursting / shrivelling of organelles Buffered resists pH changes preventing organelle + enzyme damage

Answer 18

Homogenate solution filtered to remove cell debris solution placed in a centrifuge which spins at a low speed initially then increasingly faster speeds to separate organelles according to their density

Answer 19

Supernatant first out (spun at lowest speed) is most dense = nuclei spun at higher speeds chloroplasts -> mitochondria -> lysosomes -> RER/SER -> ribosomes (least dense)

Answer 20

Involves circular DNA & plasmids replicating cytokinesis creates two daughter nuclei each daughter cell has one copy of circular DNA and a variable number of plasmids

Answer 21

1) Interphase (G1, S, G2) 2) nuclear division - mitosis or meiosis 3) cytokinesis

Answer 22

Longest stage in the cell cycle when DNA replicates (S-phase) and organelles duplicate while cell grows (G1&G2-phase) DNA replicates and appears as two sister chromatids held by centromere

Answer 23

One round of cell division two diploid, genetically identical daughter cells growth and repair (e.g. clonal expansion) comprised of prophase, metaphase, anaphase and telophase

Answer 24

Chromosomes condense and become visible nuclear envelope disintegrates in animals - centrioles separate & spindle fibre structure forms

Answer 25

Chromosomes align along equator of cell spindle fibres released from poles now attach to centromere and chromatid

Answer 26

Spindle fibre contracts (using ATP) to pull chromatids, centromere first, towards opposite poles of cell centromere divides in two

Answer 27

Chromosomes at each pole become longer and thinner again spindle fibres disintegrate + nucleus reforms

Answer 28

Used to determine proportion of cells undergoing mitosis Calculated as a percentage OR decimal MITOTIC INDEX=THE NUMBER OF CELLS IN MITOSIS/TOTAL NUMBER OF CELLS x100 for percentage

Answer 29

Describes the lateral movement of membranes with scattered embedded intrinsic and extrinsic proteins membrane contains glycoproteins, glycolipids, phospholipids and cholesterol

Answer 30

Phospholipids align as a bilayer hydrophilic heads are attracted to water hydrophobic tails repelled by water

Answer 31

Present in eukaryotic organisms to restrict lateral movement of the membranes adds rigidity to membraneresistant to high temperatures & prevents water + dissolved ions leaking out

Answer 32

Molecules must have specific properties to pass through plasma membrane lipid soluble (hormones e.g. oestrogen) very small molecules non-polar molecules (oxygen)

Answer 33

Net movement of molecules from an area of higher concentration to an area of lower concentration until equilibrium is reached passive

Answer 34

Passive process using protein channels/carriers down the concentration gradient used for ions and polar molecules e.e sodium ions and large molecules e.g. glucose

Answer 35

Net movement of water from an area of higher water potential to an area of lower (more negative) water potential across a partially permeable membrane

Answer 36

The pressure created by water molecules measured in kPa and represented by symbol ψ pure water has a water potential of 0kPa the more negative the water potential, the more solute must be dissolved

Answer 37

When the water potential of a solution is more negative than the cell water moves out of the cell by osmosis both animal and plant cells will shrink and shrivel

Answer 38

When the water potential of a solution is more positive (closer to zero) than the cell water moves into the cell by osmosis animal cells will lyse (burst) plant cells will become turgid

Answer 39

When the water potential of the surrounding solution is the same as the water potential inside the cell no net movement in water cells would remain the same mass

Answer 40

The movement of ions and molecules from an area of lower concentration to an area of higher concentration using ATP and carrier proteins carrier proteins act as selective pumps to move substances

Answer 41

When molecules bind to the receptor - ATP will bind to protein on inside of membrane and is hydrolysed to ATP / Pi protein changes shape and opens inside membrane

Answer 42

The movement of two substances across a membrane together, when one is unable to cross the membrane itself involves a cotransport protein involves active transport e.g. absorption of glucose/amino acids from lumen of intestines

Answer 43

Pathogens (bacteria, fungi, viruses) cells from other organisms of same species (transplants) abnormal body cells (tumour cells) toxins (released from bacteria)

Answer 44

Proteins on the cell-surface membrane trigger an immune response when detected by lymphocytes

Answer 45

When pathogenic DNA mutates causing a change in shape of antigen previous immunity is no longer effective as memory cells don't recognise new shape of antigen. specific antibody no longer binds to new antigen

Answer 46

Anatomical barriers to pathogens skin stomach acid lysozymes in tears

Answer 47

Non-specific immune response phagocytes become antigen presenting cells after destroying pathogen

Answer 48

Made in bone marrow and mature in thymus gland involved in cell-mediated immune response respond to antigen-presenting cells

Answer 49

Any cell that presents a non-self antigen on their surface infected body cells macrophage after phagocytosis cells of transplanted organ cancer cells

Answer 50

Have receptors on their surface that attach to antigens on APCs become activated - clonal selection

Answer 51

Some remain as helper T cells & activate B lymphocytes stimulate macrophages for phagocytosis become memory cells for that shaped antigen become cytotoxic killer T cells

Answer 52

Destroy abnormal / infected cells by releasing perforin so that any substances can enter or leave the cell and this causes cell death

Answer 53

Made in bone marrow and mature in bone marrow involved in humoral immune response involves antibodies

Answer 54

APC activates B cell B cell undergoes clonal selection and expansion - rapid division by mitosis. differentiate into plasma cells / memory B cells plasma cells make antibodies

Answer 55

derived from B lymphocytes remember specific antibody for particular antigen will rapidly divide by mitosis and differentiate in plasma cells upon secondary encounter resulting in large numbers of antibodies rapidly

Answer 56

Quaternary structure proteins made of four polypeptide chains different shaped binding site = variable region complementary to a specific antigen

Answer 57

Antibodies have two binding sites and are flexible - clumps pathogens together makes it easier for phagocytes to locate and destroy pathogen

Answer 58

Antibodies introduced into body plasma and memory cells not made as no interaction with antigen short-term immunity fast acting

Answer 59

Immunity created by own immune system - antibodies made exposure to antigen plasma and memory cells made long term immunity slower acting

Answer 60

After direct contact with pathogen through infection body creates antibodies and memory cells

Answer 61

Creation of antibodies and memory cells following introduction of an attenuated pathogen or antigens vaccination

Answer 62

Small amounts of dead or attenuated pathogens injected / ingested humoral response activated memory cells are able to divide rapidly into plasma cells when re-infected

Answer 63

Primary = first exposure to the pathogen longer time for plasma cell secretion & memory cell production for the secondary response, memory cells divide rapidly into plasma cells so a large number of antibodies made rapidly upon reinfection

Answer 64

When enough of the population is vaccinated so pathogen is not transmitted and spread easily provides protection for those without vaccine

Answer 65

A single type of antibody that can be isolated and cloned antibodies that are identical - from one type of B lymphocyte complementary to only one antigen

Answer 66

Medical treatment - targeting drugs by attaching antibody complementary to tumour cell antigen medical diagnosis - pregnancy tests

Answer 67

ELISA test which uses 3 monoclonal antibodies and enzymes to test for hCG

Answer 68

Detect the presence and quantity of an antigen used for medical diagnosis. Eg., HIV

Answer 69

Requires mice to produce antibodies and tumour cells requires a full cost-benefit analysis

Answer 70

Core = RNA and reverse transcriptase capsid = protein coat lipid envelope taken from hosts cell membrane attachment proteins so it can attach to Helper T cells

Answer 71

Attaches to CD4 receptor on helper T cells protein fuses with membrane allowing RNA + enzymes to enter reverse transcriptase makes DNA copy and this is inserted into nucleus nucleus synthesises viral proteins

Answer 72

When HIV has destroyed too many T helper cells, host is unable to produce adequate immune response to other pathogens host susceptible to opportunistic infections

Answer 73

First antibody added is complementary to antigen in well - attaches second antibody with enzyme added which attaches to first antibody as complementary. when substrate solution added enzyme can produce colour change

Answer 74

Inactive virus may become active - viral transformation non-pathogenic virus can mutate and harm cells side effects of immune response people may test positive for disease

Answer 75

Viruses are inside host cells where antibiotics cannot reach antibiotics affect parts of bacteria that viruses do not have (e.g the cell wall)

Answer 76

Removes unbound 2nd antibodies otherwise enzyme may be present → colour change → false positive

Answer 77

Microorganisms that cause a disease by releasing toxins or killing cells / tissues

Answer 78

Final stage in the cell cycle when the cytoplasm splits in two creates two new cells

Answer 79

Uncontrolled cell division can lead to the formation of tumours and of cancers many cancer treatments are directed at controlling the rate of cell division

Answer 80

Following injection of their nucleic acid the infected host cell replicates the virus particles

Answer 81

Increase in surface area or membrane increase in the number of protein channels and carrier molecules in the membranes

Answer 82

When a complementary antibody binds to an antigen this clumps pathogens together (agglutination)

Answer 83

Lipid envelope which has attachment proteins Inside the lipid envelope, there is capsid which has 2 single strand of RNA and one reverse transcriptase (catalyses the production of DNA from RNA) ]and an enzyme

Answer 84

Presence of reverse transcriptase and its consequent ability to make DNA from RNA

Answer 85

HIV enters the bloodstream and circulates the body Protein on HIV binds to protein CD4 (most frequently bind to helper T cells) Protein capsid fuses with the cell surface membrane, RNA and the enzymes of HIV enter the helper T cells HIV’s reverse transcriptase converts the virus’ RNA to DNA The new DNA is moved into the helper T cells’s nucleus and its inserted into the cells DNA The RNA DNA in the nucleus creates mRNA using the cells enzymes This mRNA contains the instructions for making new viral proteins and the RNA goes into the new HIV The mRNA passes out of the nucleus through the nuclear pore and uses the cells protein synthesis mechanisms to make HIV particles HIV particles break away from the helper T cells with a piece of it’s cell membrane, forming a lipid envelope

Answer 86

HIV cause AIDS by killing or interfering with the normal helper T cells Without sufficient helper T cells the immune system cannot stimulate B cells to produce antibodies or cytotoxic T cells that kill the infected by a pathogen and memory cells are damaged As a result, they become susceptible to to other infections and cancers

Answer 87

Binary fission

TOPIC 2: CELLS Flashcards

(112 cards)