Chapter 3.2 (cells) Flashcards

Question

Def specialised cell

Answer 1

Cell that had differentiated obtaining specific adaptions to carry out a specific function

Answer 2

How many times bigger the image produced is that the real-life object you are viewing

Answer 3

The ability to distinguish between objects that are close together

Answer 4

Magnification. =. Image size ___________________ Actual size

Answer 5

Process where cells are broken up and different organelles they contain are separated out to be analysed 2 stages= Homogenisation & ultracentrifugation

Answer 6

1. Tissue cut into small pieces and placed in cold, isotonic, buffered solution (reduces enzymatic action that could break down cell) 2. Ground into smaller pieces using homognizer ( to release organelles) 3. Homogenate is filtered ( remove large particles/ complete cells) 4. Suspension of homogenate placed in centrifuge 5. Spun at slow speeds to separate large fragments and supernatant liquid 6. Larger fragments removed and supernatant re-spun at faster speed (Different spin speeds separate different cells) 7. Continue this and smaller and smaller fragments will be separated.

Answer 7

1mm = 1,000 μm

Answer 8

1mm = 1,000,000 nm

Answer 9

Light microscope Transmission electron microscope (TEM) Scanning electron microscope (SEM)

Answer 10

See notes Light magnification around 1,000x Resolution 200nm TEM Magnification 2,000,000x Resolution 0.1 nm SEM Magnification 1,000,000 Resolution 1 nm

Answer 11

1. Complex preparation produces artefacts (errors) that are difficult to identify and distinguish 2. Specimens must be dead to be observed 3. Cannot be viewed directly

Answer 12

**interphase** - G1 (gap 1) - S phase (DNA synthesis) - G2 (gap 2) **Mitosis**

Answer 13

**G1** first growth phase - protein synthesis - increase volume of cytoplasm - increase organelles If cells don’t divide they exit the cycle at this stage and entre G0

Answer 14

**S Phase** - DNA replication/ synthesis - histone proteins synthesised

Answer 15

**G2 phase** second growth phases - proteins synthesised - increased energy stores - chromosomes begin to condense prior to nuclear division - increase volume of cytoplasm - increase organelles

Answer 16

1) Prophase 2) Metaphase 3) Anaphase 4) Telophase

Answer 17

- Chromosomes become visible as shorten and thicken - nuclear envelope breaks open - spindle fibres start to form (- centrioles move to opposite ends of cell)

Answer 18

- chromosomes can be seen as X shaped structures (2 chromatids joined at the centre) - chromosomes line up along equator (middle of cell) - chromosomes attached to the spindle fibres at centromere

Answer 19

- microtubes in spindle fibres contract pulling chromatids to opposite poles of cell

Answer 20

-groups of chromatids form two new nuclei + chromosomes uncoil - **cytokinesis** > division of cytoplasm to produce two new cells

Answer 21

Eukaryotic cells - cell cycle (mitosis) Bacteria cells - binary fission

Answer 22

Mitosis is a controlled process. Uncontrolled cell division can lead to formation of tumours and cancer

Answer 23

- replication of circular DNA + plasmids - division of cytoplasm to produce 2 daughter cells, each with a single copy of circular DNA ans a variable number of copies of plasmids

Answer 24

Being non-living viruses don’t do cell division. 1) LYTIC CYCLE After injecting their genetic information, host cell replicates the virus particles 2) LYSOGENIC CYCLE Injected genetic material but the DNA stays hidden inside host cell’s DNA until triggered to go into the lytic cycle

Answer 25

MI= number of cells with condensed chromosome (in cell cycle) _____________________________________________________________. X 100 Total number of compete cells

Answer 26

**Phospholipid bilayer** **Cholesterol**in the fatty acid tail sections **Integral proteins** that span the entire bilayer **Peripheral proteins** that anchored at phosphate head layer **glycolipids** that come out of the top of the bilayer

Answer 27

FLUID - components aren’t in fixed shapes/positions they are constantly moving MOSAIC - all components are different shapes and sides yet still fit tightly together

Answer 28

STRUCTURE: (Similar to phospholipid-) 2 fatty acids, glycerol + Sugar head FUNCTION: Electrical insulation and cell signalling

Answer 29

STRUCTURE: Different from phospho and glyco lipids FUNCTION: Acts in the hydrophobic section of bilayer: Maintain/ regulate membrane fluidity

Answer 30

STRUCTURE: Normal primary, secondary,tertiary structures of proteins Anchored into phosphate heads (easily removed by altering pH) FUNCTION: Anchors cytoskeleton to it

Answer 31

STRUCTURE: Normal primary, secondary,tertiary structures of proteins Embedded into hydrophobic part of bilayer (spans entire membrane) FUNCTION: Transports substances through it

Answer 32

1) transport 2) compartmentalisation of cells 3) cell communication 4) cell recognition 5) cell adhesion

Answer 33

Must be: -non polar/ hydrophobic - small (E.g O2, steroid, CO2) - lipid soluble Triglycerides, proteins, glucose = too large

Answer 34

The net movement of particles from area of high conc. to area of lower conc. down the conc. gradient

Answer 35

1. Steepness of concentration gradient 2. Size of particles 3. Temperatures 4. Surface area of membrane 5. Distance across

Answer 36

Similar to diffusion, it occurs down a concentration gradient, but it differs as special **protein channels** & **carrier proteins** are envolved

Answer 37

A protein that forms a pore in a cell membrane and allows the facilitated diffusion of charged particles

Answer 38

A protein in cell membrane that allows the facilitated diffusion of large molecules

Answer 39

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

Answer 40

Any substance that is dissolved in a solvent to form a solution

Answer 41

KiloPascals (kPa)

Answer 42

The movement of molecules or ions into or out of a cell from a region of lower conc. to a region of higher conc. against the conc. gradients using ATP and carrier proteins

Answer 43

- carrier protein on membrane binds to molecule/ion to be transported (at receptor site) - inside cell ATP bind to protein and is hydroylsised into ADP &Pi releasing energy causing protein to change shape and open to opposite side of membrane - molecule/ ion released - Pi released from protein causing it to revert to original shape ready to repeat

Answer 44

**Active transport example** 3 Na+ ions removed & 2 K+ actively taken in Carrier proteins require energy from ATP for this movement. This is used to set up conc. gradients & create nerve impulses

Answer 45

-absorption of amino acids/ glucose into ileum epithelial cells

Answer 46

1) **Na+ actively transported** with use of ATP out of epithelial cells and K+ ions are drawing in- sodium potassium pump using carrier proteins 2) creates **high conc. Na+ in lumen** of intestine than inside cell 3) Na+ **diffuse** into cells (through symport co-transport proteins) carrying either **amino acid/glucose** molecule into cell with them into epithelial cell 4) the glucose/amino acid pass into the blood by **facilitated diffusion** by carrier proteins in the basal membrane

Answer 47

The passage of water for a region where of higher water potential to a region of lower water potential through a selectively permeable membrane

Answer 48

Water potential (Ψ ) -ability for H2O molecules to move Pure water has Ψ of 0 In a concentration solution Ψ is a negative value

Answer 49

If too much water moves into an animal cell by osmosis they will swell and burst Water is stored in the vacuole. Vacuole pushes against cells wall= turgid this prevent them wilting. Cells with vacuoles completely away from cell wall = plasmolysed

Answer 50

**Hypotonic** - solution with **Higher** water potential. [ water moves out of cell] **isotonic** - solution with **identical** water potential **hypertonic** - solution with **lower** water potential [ water moves into cell]

Answer 51

Marker molecule that can be detected by antibodies and trigger an immune response (Specific to each cell/pathogen)

Answer 52

Marker molecule that can be detected by antibodies and trigger an immune response (Specific to each cell/pathogen)

Answer 53

A protein found in the blood that is produced by plasma cells (B. Cells) which binds to antigens as part of the immune response Also called Immunoglobulin proteins

Answer 54

Protein made of 4 polypeptide chains forming a Y shaped structure - 2 heavy chains - 2 light chains Constant regions and variable regions Disulfide bridges between polypeptide chains

Answer 55

Variable - contain unique sequence of amino acids part of antibody that binds to antigens Constant - always have same amino acid sequence - heavy chain constant regions bind to receptors on some types of white blood cells

Answer 56

- variable regions of each antibody has a unique order of amino acids in that regions that form the antigen-binding site - different antibody proteins will fold into unique tertiary 3D shape - each antigen-binding site will have a complementary shape specific to only one type of antigen molecule

Answer 57

1. **Agglutination** Each antibody can bind to 2 antigens this clumps together microbes making them easier for phagocytes to engulf. 2. **Opsonisation** Constant regions of antibody bind to receptor on macrophage, microbe ingested by phagocytosis forming phagosome, lysosome fused with phagosome releasing chemicals and hydrolytischem enzymes to destroy pathogen 3. **Destruction by complement** The constant regions of the heavy change binds to and activities complement which are proteins in the plasma that punch holes in bacterial cell membranes

Answer 58

- inflammatory response - blood clotting Phagocytosis

Answer 59

1) contact and **binding** between receptor molecule and antigen on foreign matterial 2) pseudopodia (feet) form on phagocyte and **ingestion of bacteria by endocytosis** 3)formation of a **phagosome**( vesicle) plasma membrane surround the bacterium pinches and forms phagosome 4) lysosome fuses with phagosome to form vesicle = **phagolysosome** 5) lysosome containers hydrolytic enzymes that digest bacteria and break molecules down 6) products of digestion - absorbed - released by exocytosis - presented on phagocyte’s surface

Answer 60

Phagocytosis - for solid matter (cell eating) Pinocytosis - for liquid matter (cell drinking)

Answer 61

Virus particle - core contains RNA (genetic material) - core contains proteins including enzyme reverse transcriptase - outer protein coating = capsid - extra outer layer = envelope Attachment protein

Answer 62

HIV replicates inside Helper T-cells 1) protein on HIV binds to CD4 protein most frequently on helper T-cells 2) protein capsid fuses with cell membrane and releases RNA into T-cell along with enzymes 3) HIV reverse transcriptase converts virus’s RNA into DNA stand 4) Made viral DNA moved and inserted into helper T-cell’s DNA 5) HIV DNA creates mRNA using cell’s enzymes - this mRNA makes viral proteins & RNA 6) cell’s protein synthesis makes HIV particles which bind to cell surface membrane of Hkeper T-cell and form lipid envelope 7) viral particles go to infect new cells

Answer 63

HIV causes aids by killing/ interfering with function of Helper T-Cells Without these T-cells the immune system cannot stimulate B-cells to produce antibodies or cytotoxic T-cells that kill infected cells As a result - more susceptible to infections - normal infections can be serious or deadly

Answer 64

1) Virus rely on host ells to carry out metabolic activities so lack their own metabolic structures and pathways which antibiotics usually target 2) viruses have proteins coats rather than more in cell walls therefore cannot break through and get into particle 3) no site for antibiotics to bind when viruses are within host cells

Answer 65

Immunoglobulin proteins Produced by B-cells in response to antigens during immune response

Answer 66

Protein made up of 4 polypeptide chains ( 2 heavy and 2 light) forming a Y-shaped structure help together with disulphide bridges There are variable regions and contrast regions

Answer 67

Variable regions - unique sequence of amino acids that bind to specific antigen Constant regions- always the same (heavy chain) so region can bind to repertory on some types of white blood cells

Answer 68

- variable regions of each antibody has a unique order of amino acids (primary structure) in the region that forms that antigen binding site - different antibody proteins will fold into different 3D shapes (each has a unique tertiary strucutre) - each antigen-binding site will have a complementary shape specific to only one type of antigen molecule.

Answer 69

1) AGGLUTINATION Each antibody can bind to 2 antigens this clumps them together making it easier for phagocytes to engulf them 2) OPSONISATION Constant region of antibody binds to receptors on macrophage, microbe then ingested by phagocytosis 3) DESTRUCTION BY COMPLEMENT Constant region of heavy change binds to and activates complements- these are proteins in plasma that punch holes in bacteria cell membranes

Answer 70

In bone marrow

Answer 71

MHC- are protein marker found on cel surface which presents antigen in infected and abnormal cells to signal T-cells to attack

Answer 72

1) macrophage presents antigen on MHC molecule and T-cell binds to become helper T-cell 2) divides by mitosis to produce clone identical T-cells 3) activated T-helper cells facilitate activity of other immune cells 4) activated T-cells produce cytokines (interleukins) to stimulate phagocytosis also stimulate mitosis of B-cells

Answer 73

These cells identify abnormal/infected cells. When attached it releases a glycoprotein called perforin Perforin destroys cells by creating holes in the membrane

Answer 74

The process of matching the antigens on an antigen presenting cell with the antigen receptors on B and T- lymphocytes

Answer 75

The production of many genetically identical daughter cells through cell division of the activated B or T- lymphocyte after clonal selection

Answer 76

A type of disease immunity that occurs when a large proportion of a population are vaccinated against a disease which prevents the spread of the diseases to unvaccinated individuals

Answer 77

Identical antibodies that have been produced by an immune cell that has been cloned from a patent cell

Answer 78

1) surface antigens of invading pathogens are complementary to a receptor (antibody) on B-cell and binds 2) B-cell activated causing it to engulf antigen by endocytosis and digest it 3) displaying the antigen fragments bound to its unique MHC molecules 4) helper T-cells attach to antigen and MHC on B-cells activating it 5) cytokines secreted by T-cell help B- cell to divide by mitosis and mature into producing clone plasma cell. 6) plasma cells produce & secrete specific antibody into the blood 7) the antibodies attach to antigens on the pathogen and destroy it in a variety of ways 8) some B-cells develop into memory cells that circulate in the blood and tissue fluid for future infections ( secondary immune response)

Answer 79

They release cytokines that stimulate: - maturation of B-lymphocytes - production of memory B-cells - Activation of Cytotoxic T cells which destroy foreign cels using performing - increased rate of phagocytosis

Answer 80

A suspension of **antigens** that are intentionally put into the body to induce **artificial active immunity**. It results in a specific immune response where **antibodies** were released by **plasma cells**

Answer 81

Memory cells are made. The immune system remembers the antigen when reencountered and produces antibodies to it, in what is a faster, stronger secondary response

Answer 82

A sufficient large proportion of the population has been vaccinated (and therefore immune) Which makes it difficult for a pathogen to spread within that population Those people not immunised (children or those with weakened immune system) are protected and unlikely to contract it as levels of diseases are low. *the proportion of the population that needs to be vaccinated in older to achieve herd immunity is different for each disease*

Answer 83

Some pathogens are complicated, vaccines are not possible Some people don’t want vaccinations Lack of public health facilities e.g fewer trained personnel Unstable political situation

Answer 84

Some pathogens are complicated, vaccines are not possible Some people don’t want vaccinations Lack of public health facilities e.g fewer trained personnel Unstable political situation

Answer 85

Advantages: - can give a lifetime of protection (very effective) - generally harmless (do not cause disease themselves) Disadvantage - poor response in some individuals - antigenic variation (variations in antigens on cell surface) - antigenic concealment

Answer 86

They use animals Can be side effects Testing for vaccines can be unethical Herd immunity Expensive vaccines and diseases that are almost eradicated Individual health risks versus protecting the population

Answer 87

In active immunity the body produces its own antibodies by plasma cells to stimulate immune response. Whereas, passive immunity happens without bodies own immune response (for example when babies are given antibodies by mother through breast milk) Active immunity is slower acting but lasts longer response. Passive immunity is faster acting as antibodies already present but shorter response as only acts while antibodies last.

Answer 88

1. Immunise mouse with antigen 2. Immune response occurs, antigen-specific B-cells selected and divide by mitosis 3. Spleen removed and B-cells isolated 4. B-cells and myeloma cells grown together and fuse forming hybridomas 5. Hybridomas which secrete correct antibodies are identified and cultured 6. Monoclonal antibodies harvested from culture and purified

Answer 89

1) to treat diseases By binding to and blocking action of certain molecules *e.g HER-2 receptor which cause growth of breast cancer cells* 2) to diagnose disease/ pregnancy/ research By binding to specific molecules *monoclonal antibodies which bind to hCG (only produced by implanted embryo) used in pregnancy testing kits

Answer 90

Antibodies have variable regions that bind to complementary shaped antigen. These antibodies bind to one specific target molecule and inhibits that action of target molecules that cause disease In diagnostics, antibodies bind to specific target molecules produced as a result of the disease, it prevents false positive results.

Answer 91

1) antigen is bound to the bottom of the reaction vessel 2) blood plasma sample is added to the reaction vessel - antibodies complementary to antigen bind to bound antigen = primary antibodies 3) the vessel is washed out to remove any unbound antibodies 4) secondary antibodies with enzymes attached bind to the primary antibodies 5) reaction vessel rewashed to remove any unbound secondary antibodies (this prevents false positives) 6) solution containing enzyme’s substrate is added which reacts with the enzyme attached to secondary antibodies. If secondary antibodies are present and attached then colour product produced so there is a colour change

Answer 92

Phagosome fuses with lysosome Pathogen gets destroyed by hydrolytic enzymes Pathogen antigen displayed on the cell membrane

Answer 93

Helper T-cell binds to the antigen This helper t-cell stimulates specific B-cell B-cell divides by mitosis Forming plasma cells that release antibodies

Answer 94

- maturation of B-lymphocytes into plasma cells - production of memory cells - activation of cytotoxic t-cells - increases the rate of phagocytosis

Chapter 3.2 (cells) Flashcards

(122 cards)