Unit 2 Flashcards
1
Q
7 structures in a nucleus
A
-Nuclear envelope
-Nuclear pore
-Nucleoplasm
-Chromatin
-Rough Endoplasmic Reticulum
-Smooth Endoplasmic Reticulum
-Nucleolus
2
Q
Nuclear envelope
A
-Double membrane that surrounds the nucleus.
-Controls entry and exit of materials in and out.
3
Q
Nuclear pore
A
Allows molecules to pass out the nucleus like RNA.
4
Q
Nucleolus
A
Small spherical region which assembles ribosomes.
5
Q
Chromatin
A
Makes up chromosomes.
6
Q
Rough Endoplasmic Reticulum
A
Synthesis of proteins.
7
Q
Smooth Endoplasmic Reticulum
A
Synthesise, store and transport lipids and carbohydrates.
8
Q
Function of the nucleus
A
-Control centre and protein synthesis.
-Genetic material in DNA and chromosomes.
-Manufactures ribosomal RNA and ribosomes.
9
Q
4 structures in a mitochondrion
A
-Inner Membrane
-Outer Membrane
-Cristae
-Matrix
10
Q
Inner and Outer Membrane
A
Entry and exit of material.
11
Q
Cristae
A
Many folds that create a larger surface area to which enzymes can bind to in order to aid in respiration.
12
Q
Matrix
A
Contains lipids, DNA, proteins, ribosomes and enzymes used in respiration.
13
Q
Golgi Apparatus (6)
A
-Add carbohydrates to proteins to form glycoproteins.
-Produce secretory enzymes.
-Secrete carbohydrates.
-Transport, modify and store lipids.
-Forms lysosomes.
-Molecules ‘labelled’ with destination.
14
Q
Golgi Vesicles
A
Vesicles transport finished products to cell surface to fuse with membrane and contents are released.
15
Q
Lysosomes (5)
A
-Bags of digestive enzymes- up to 50 enzymes.
-Hydrolyse phagocytic cells.
-Completely breakdown dead cells (autolysis).
-Exocytosis- release enzymes to outside of cells to destroy material.
-Digest worn out organelles for reuse of material.
16
Q
Ribosomes
A
-Small, made up of two subunits of protein and rRNA.
-80s- larger, eukaryotes.
-70s- smaller, prokaryotes, mitochondria, chloroplasts.
-Site for protein synthesis.
17
Q
Vacuole
A
-Tonoplast is the single membrane around the vacuole.
-Keeps cell turgid and supportive.
-Temporary store of sugars and amino acids.
-Pigments colour petals to attract pollinators.
18
Q
3 Structures in Chloroplasts
A
-Granum
-Thylakoid
-Stroma
19
Q
Granum
A
A single unit within a thylakoid.
20
Q
Thylakoid
A
Folded membranes embedded with pigment.
21
Q
Stroma
A
Contains enzymes for photosynthesis.
22
Q
Cell wall
A
-In plant and fungi cells.
-Plants- made of microfibrils of cellulose.
-Fungi- made of chitin, nitrogen-containing polysaccharide.
-Provides structural strength.
23
Q
Plasma Membrane
A
-Phospholipid bilayer- molecules embedded within and attached on outside (proteins, carbohydrates, chloestrol).
-Controls the entrance and exit if molecules.
24
Q
9 Structures in a Prokaryotic Cell
A
-Cytoplasm
-Chromosomal DNA
-Cell membrane
-Ribosomes- 70s
-Plasmids
-Cell wall
-Capsule
-Flagellum
-Plasmids
25
Cell wall in prokaryotic cell is made of...
Murein/ peptidoglycan
26
5 Structures in a Virus
-Lipid envelope
-Capsid
-Attachment protein
-Genetic material (RNA)
-Reverse transcriptase (enzyme!!!!!!!)
27
Magnification
How many times bigger the image is compared to the object.
28
Resolution
The ability to distinguish between two points.
The minimum distance apart the two objects can be in order for them to appear as seprate items.
29
3 types of Microscopes
-Light/optical microscope
-Scanning Electron Microscope
-Transmission Electron Microscope
30
Scanning Electron Microscopes
-Produces a 3D image.
-Specimen doesn't need to be thin.
-Uses a beam of electrons.
31
Transmission Electron Microscopes
32
Limitations of electron microscopes
33
Mitosis and its stages:
A type of cell division that results in clones.
Stages:
-Interphase (G1, S, G2)
-Prophase
-Metaphase
-Anaphase
-Telophase
-Cytokinesis
34
Interphase
-The stage where all the subcellular structures are replicated.
-G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth).
35
Prophase
-Chromosomes become visible.
-Nuclear membrane disintegrates.
-Nucleolus disappears.
-Centrioles move to opposite poles forming spindle network.
36
Metaphase
-Spindle fibres form and attach to centromere.
-Chromosomes align along equator.
37
Anaphase
-Spindle fibres shorten/ contract.
-Centromere divides.
-Pulling chromatids to opposite poles of the cell.
38
Telophase
-Chromosomes uncoil becoming longer and thinner.
-Nuclear envelopes reform= 2 nuclei.
-Spindle fibres/ centrioles break down.
39
Cytokinesis
-Cell membrane is formed around new cells.
-Produces two genetically identical daughter cells with a diploid nucleus.
40
Binary fission
-The circular DNA molecule replicates and both copies attach to the cell membrane.
-Plasmids replicate.
-Cell membrane begins to grow between the two DNA molecules and begins to pinch inwards, dividing the cytoplasm into two.
-New cell wall is formed between the 2 molecules of DNA dividing cell into 2 identical daughter cells (single copy of circular DNA and diff no of plasmids).
41
Importance of mitosis
-Growth
-Repair
-Reproduction
42
3 stages of cell cycle:
-Interphase
-Nuclear division
-Cytokinesis
43
Cancer and control of mitosis
-Cancer is the uncontrollable division of cells.
-Damage to the cells that regulates mitosis so uncontrollable division.
-Malignant and benign.
44
Treatments of cancer:
-Some disrupt spindle fibre activity/ formation- chromosomes can't attach to spindle by their centromere- can't be separated to opposite poles- prevents mitosis.
-Some prevents DNA replication during interphase- can't make 2 copies of each chromosomes- prevents mitosis.
45
Structures in cell plasma membrane:
-Phospholipids
-Cholesterol
-Proteins
-Glycolipid
-Glycoprotein
46
Function of phospholipids
-Allow lipid-soluble substances to enter and leave the cell.
-Prevents water-soluble substances from entering and leaving the cell.
-Make the membrane flexible and self-sealing.
47
Function of cholesterol
-Reduce lateral movement of other molecules including phospholipids.
-Makes the membrane less fluid at high temperatures.
-Prevent leakage of water and dissolved ions from the cell.
48
Function of proteins
-Provide structural support.
-Acts as channels transporting water-soluble substances across the membrane.
-Allow active transport across membrane through carrier proteins.
-Form cell-surface receptors for identifying cells.
-Help cells adhere together.
-Act as receptors e.g. for hormones.
49
Function of glycolipids
-Acts as recognition sites.
-Helps maintain stability of membrane.
-Helps cells attach to one another and form tissues.
50
Function of glycoproteins
-Acts as recognition sites.
-Helps cells to attach to one another and form tissues.
-Allow cells to recognise one another. e.g. lymphocytes recognise own cells.
51
What can freely diffuse across bilayer?
Small, lipid-soluble, non-polar molecules.
52
Fluid-mosaic model
Fluid- individual phospholipids molecules can move relative to another. Gives membrane a flexible structure so it's constantly moving.
Mosaic- proteins are embedded in the bilayer, varying in shape, size ad pattern the same way as tiles.
53
Diffusion
The net movement of molecules and ions from a region where they are more highly concentrated to one where their concentration is lower until evenly distributed.
54
What effects rate of diffusion?
-Concentration gradient.
-Thickness of exchange surface.
-Temperature.
-Area over which diffusion occurs.
55
Facilitated diffusion
-Passive process.
-Relies on the inbuilt motion (kinetic energy) of the diffusing molecules.
-Occurs down a concentration gradient.
-Uses proteins channels and carrier proteins.
56
Protein channels and facilitated diffusion
-Form water-filled hydrophilic channels across membrane.
-Allow water-soluble ions to pass through.
-Channels are selective and only open to certain molecules.
57
Carrier proteins and facilitated diffusion
58
Osmosis and its nature
The passage of water from a region where it has a higher water potential to a region where it has a lower water potential through a selectively permeable membrane.
59
Water potential
60
Osmosis and animal cells
61
Osmosis and plant cells
62
Active transport
The movement of molecules or ions into or out of a cell from a region of lower concentration to a region of higher concentration using ATP and carrier proteins.
63
Active transport process
-The carrier proteins span the plasma membrane and bind to the molecule or ion.
-The molecule or ion binds to receptor sites on the carrier protein.
-On the inside, ATP binds to the protein, causing it to split into ADP and Pi. Protein changes shapes and opens to the opposite side of the membrane.
-Molecule or ion is released to other side of membrane.
-Pi is released from protein reverting it to the original shapes.
-Pi and ADP combine to form ATP during respiration.
64
Conditions for active transport
-Metabolic energy in the form of ATP.
-Carrier protein molecules which act as 'pumps'.
-Specific substances are transported.
65
Co-transport of glucose process
1. Na+ are actively transported out of the epithelial cell, by the sodium-potassium pump, into the blood by carrier proteins.
2. Maintains a higher concentration of Na+ in lumen than inside cell.
3. Na+ ions diffuse into the epithelial cell down a concentration gradient where either an amino acid or glucose molecule attaches to it using a co-transport pump.
4. The glucose/amino acid pass into the blood plasma by facilitated diffusion using another type of carrier.
66
Villi
-Possess finger-like projections called microvilli.
-Form a 'brush border'.
-Increases surface area over which molecules can diffuse due to the larger density of protein channels and carrier proteins.
67
Products of digestion
-Carbohydrates and proteins are digested continuously, so greater concentration of glucose and amino acids within the lumen.
-Continuous blood flow maintains a concentration gradient between blood and lumen.
68
Self from non-self antigens
69
Phagocytosis process
-Pathogen attaches to the surface receptors on the surface of the phagocyte.
-Engulf the pathogen to form a vesicle called a phagosome.
-Lysosomes fuse with it forming a phagolysosome.
-Lysozyme (enzyme) is released hydrolysing pathogen.
-Useful products are absorbed and useless products are excreted.
70
Antigen
Proteins on the cell surface of an invading particle that is detected as non-self triggering an immune response.
71
T Lymphocytes
-Mature in the thymus gland.
-Cell-mediated response.
72
B Lymphocytes
-Mature in the bone marrow.
-Humoral response.
73
Cell-mediated immunity
1. Pathogens invade body cells or are taken in by phagocytes.
2. The phagocyte presents antigens on its surface.
3. Receptors on helper T cells fit exactly into antigens.
4. Attachments activates the T cells and it divides by mitosis and forms a clone of genetically identical cells.
5. Cloned T cells:
a) develop into memory cells to produce rapid secondary response.
b) stimulates phagocytes to engulf pathogens by phagocytosis.
c) stimulates B cells to divide and secrete antibodies.
d) activates cytotoxic T cells.
74
Cytotoxic T Cells
-Puncture the cell membrane.
-Inject perferin.
-Cell structure dissembles and cell dies.
75
Humoral immunity
1. Surface antigens are taken up by B cells.
2. B cells process the antigens and present them on their surface.
3. Helper T cells attach to processed antigens therefore activating the B cell.
4. B cells then divide by mitosis producing clones of plasma cells.
5. Cloned plasma cells produce and secrete specific antibodies that are complementary.
6. Antibody attaches to antigens on pathogen and destroys them.
7. Some B cells develop into memory cells that stay in the blood to produce a faster secondary response.
76
Plasma cells
-Secrete antibodies into the blood plasma.
-Antibodies lead to destruction of antigens.
-Primary immune response.
77
Memory cells
-Responsible for secondary immune response.
-Live in the blood stream for longer sometimes even decades.
-Faster and more efficient 2nd response.
78
Antigenic variation
The surface receptors on lymphocytes and memory cells are complementary in shape to ONLY ONE antigen.
79
Structure of antibody
Draw it!!!
80
2 ways in which antibodies destruct antigen
-Agglutination- clump together antigens to make phagocytosis easier.
-Markers- stimulates phagocytes to engulf bacterial cell to which they are attached.
81
Monoclonal antibodies
Identical antibodies that have been produced by an immune cell that has been cloned from a parent cell.
82
Uses of monoclonal antibodies in medicine
-Targeting cells by attaching drugs onto monoclonal antibodies that find with antigen.
-Medical diagnosis.
-Pregnancy testing.
83
Monoclonal antibodies in pregnancy testing
-Woman produces human chorionic gonadatrophin (hCG) in urine.
-Monoclonal antibodies on test strip complementary to antigen on hCG.
-Antigen-antibody complex is formed.
-Moves up test strip and produces a line.
84
Ethical issues of monoclonal antibodies
-Uses mice.
-Full knowledge of benefits and risks.
-Dangerous side effects.
85
Passive immunity
-Introducing of antibodies into individuals from an outside source.
-No long term immunity.
86
Active immunity
-Stimulating the production of antibodies by the individuals' own immune system.
-Long-lasting immunity.
-Two types- Natural, Artificial.
87
Natural active immunity
Individual becomes infected by disease under normal circumstances.
88
Artificial active immunity
Individual is exposed to vaccine and they undergo an immune response due to it.
89
Vaccinations
The introduction of a dead or inactive pathogens to stimulate an immune response and provide long term immunity
90
Features of successful vaccine program
-Economically available in sufficient amount for vulnerable population.
-Few side effects.
-Means of producing, storing and transporting vaccine.
-Means of administering vaccine properly.
-Vaccinate vast majority to get herd immunity.
91
Herd immunity
A type of disease immunity that occurs when a large population are vaccinated against a disease which prevents the spread of disease to unvaccinated individuals.
92
Vaccinations may not work. Why?
-Fails to induce immunity.
-Develop disease and pass it on to others.
-Pathogens mutate, antigenic variability.
-Many varieties of particular pathogen.
-Pathogens 'hide' inside body.
-Objections to vaccine (religious, ethical).
93
Structure of HIV
Draw it!!!
94
Replication of HIV
-Attachment protein on HIV attaches to the CD4 receptor on the T helper cell.
-Capsid fuses with the cell membrane of the T helper cell.
-RNA and reverse transcriptase enter the cell.
-Enzyme turns RNA into DNA.
-Fuses with cell's DNA.
-During transcription of cell, mRNA for virus is formed.
-Viral particle is produced which break away from the T helper cell with a piece of the cell-surface membrane forming the lipid envelope of the HIV particle.
95
HIV--->AIDS
-T helper cells drop below critical level.
-Cannot produce immune response and therefore person is more susceptible to infections.
-Leads to AIDS.
96
ELISA test
-Apply sample to surface.
-Wash the surface several times to remove any unwanted pathogens.
-Add the antibody that is complementary to the antigen that you're detecting.
-Wash the surface to remove excess antibody.
-Add a second antibody, with an enzyme attached, which is complementary to the first antibody.
-Add colourless substrate of enzyme. Enzyme acts on substrate making it change colour.
-The amount of antigen present is relative to the intensity of colour that develops.
97
Why do antibiotics not work on viruses?
-Bacterial cells have cell walls made of murein (peptidoglycan).
-Viruses have a protein coat.
-Antibiotics inhibits enzymes that assemble cross-linkage in cell walls.
-They can do this on bacteria cells and not viruses as surface isn't exposed.
