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BIOL112 > CELS199 Exam > Flashcards

CELS199 Exam Flashcards

1
Q

What is a cell?

A

The basic unit of structure and function for an organism, simplest collection of matter that can live and replicate itself

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2
Q

3 main characteristics of a eukaryote

A

Complex internal organisation of organelles, large 10-100 micro meters, have a nucleus, uni/multi cellular

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3
Q

3 main characteristics of a prokaryote

A

Simple cells, small 1-5 micro meters, no nucleus, unicellular no membrane bound organelles

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4
Q

List the characteristics of life

A

Cellular organisation, reproduction, metabolism, homeostasis, heredity, responses to stimuli, growth and development, adaptation through evolution

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5
Q

What type of microorganisms are viruses?

A

Acellular

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6
Q

What are the 4 basic features of all living cells?

A

plasma membrane, cytosol, chromosomes, ribosomes

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7
Q

What is the definition of a plasma membrane?

A

membrane boundary to the cell, selective barrier that regulates the cells chemical composition

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8
Q

What is the difference between cytosol and cytoplasm?

A

cytosol is the semi fluid portion of the cytoplasm and the cytoplasm refers to the cytosol and all of the cellular structures that are bounded by the plasma membrane

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9
Q

What is the definition of chromosomes?

A

a structure that carries the genetic makeup of the cell, found in the nucleus (eukaryotes) or nucleoid region (prokaryotes)

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10
Q

What is the definition of ribosomes?

A

complex of ribosomal RNA and proteins that function as a sit of protein synthesis, have large and small subunit

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11
Q

What kingdoms are in the domain Eukarya?

A

plantae, animalia, fungi, protist kingdoms (bacteria and archaea are prokaryotes)

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12
Q

What are the common organelles found in most eukaryotic cells?

A

Nucleus, mitochondrion, sER, rER, golgi

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13
Q

What organelle is only found in animal cells and what organelles are only found in plant cells?

A

animal - lysosome
Plant - chlorplast and central vacuole

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14
Q

Common structure found in some eukaryote cells?

A

flagella

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15
Q

Structures only found in plant cells?

A

cell wall, plasmodesmata

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16
Q

What size are mitochondria and chloroplasts?

A

M - 1-10 micrometers
C - 2-5 micrometers

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17
Q

What are the four main biological molecules found in cells?

A

carbohydrates, lipids, proteins, nucleic acids (all polymers except lipids)

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18
Q

Wha is the order the number of higher order structures?

A

building blocks, macromolecules, supramolecular assemblies, organelles

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18
Q

What are the components of the building blocks?

A

Amino acids, simple carbohydrates, nucleotide bases, lipids

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19
Q

What are the components of macromolecules?

A

proteins, DNA, RNA (nucleic acids), complex carbohydrates

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20
Q

What are the components of super molecular assemblies?

A

membranes, ribosomes, chromatin

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21
Q

What are the components of organelles?

A

nucleus, mitochondria, golgi, ER

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22
Q

What is the monomer subunit for carbohydrates?

A

monosaccharides, for complex its polysaccharides

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23
Q

What are the functions of carbohydrates?

A
  1. Recognition 2. Energy 3. Structure (cellulose)
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24
Q

What are the monomer subunits of nucleic acids?

A

nucleotides (DNA, RNA), polynucleotides

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25
Q

What is the basic structure of a nucleic acid?

A

A sugar, nitrogenous base, and a phosphate group

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26
Q

What is the basic structure of a carbohydrate?

A

hexose or Pentose or cellulose strand things

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27
Q

What are the functions of nucleic acids?

A

DNA = inheritance (chromosomes), informational molecule, RNA controls protein synthesis

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28
Q

What is the monomer of proteins?

A

amino acids, different R group

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29
Q

Definition and functions of proteins?

A

molecules by which cells perform their functions in the whole organism, structural = collagen, regulatory = insulin, contractile = actin, myosin, protective = antibodies

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30
Q

4 key characteristics of a lipid

A

Don’t form polymers, smaller than other macromolecules, heterogenous (very different structures), all are hydrophobic (not soluble in water)

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31
Q

What are the functions of lipids?

A

Structural (phospholipid and cholesterol in the cell membrane), regulatory, energy (TAG)

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32
Q

What must a cell do?

A

manufacture cellular materials, obtain raw materials, remove waste, generate required energy, control all of the above

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33
Q

What are the 3 main things organelles do?

A

form concentration gradients, package for transport or export, protect vital parts of the cell

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34
Q

What are the 3 main parts of the phospholipid bilayer?

A

hydrophilic phosphate heads, hydrophobic fatty acid tails, integral membrane proteins

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35
Q

What does cholesterol do in the phospholipid bilayer?

A

aids fluidity in animal cells, buffer to changes in temperature, at higher temps it interacts with the hydrocarbon tails for the membrane to be less fluid, at lower temps it limits how tightly the hydrocarbon tails pack together to retain fluidity

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36
Q

What diffuses through the phospholipid bilayer?

A

Lipid soluble (hydrophobic) molecules like steroid hormones, gases (CO2), can occur in either direction

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37
Q

What does the phospholipid bilayer restrict movement of?

A

water soluble molecules (hydrophilic) and charged molecules like glucose, water, ions

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38
Q

Explain facilitated diffusion

A

Movement of specific hydrophilic molecules requires membrane proteins (channel or carrier proteins), passive, water uses aquaporins (osmosis, high to low)

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39
Q

What are proton pumps an example of?

A

active transport, have internal concentration different to its surroundings

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40
Q

What is signal transduction?

A

protein changes shape when a chemical messenger binds, this transfers a signal from on side of the membrane to another (hormone)

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41
Q

What is cell recognition?

A

some glycoproteins act as a identification tag

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42
Q

What is intercellular joining?

A

membrane proteins of adjacent cells may hold them tight together (gap and tight junctions)

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43
Q

What do membrane proteins link and help do?

A

link the cytoskeleton and Extracellular matrix, helps maintain cell shape and coordinate Extracellular and intracellular changes

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44
Q

Explain the process of synthesis of secretory proteins

A

Synthesised on the surface of the rER, as they are synthesised they enter the lumen, membrane then surrounds the proteins forming a transport vesicle, they are processed via the Endomembrane system, same process for membrane bound proteins and those going to be excreted from the cell.

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45
Q

What is the golgi complex?

A

series of membrane sacs and associated proteins, has polarity (direction), cis (arrive) and trans (leave) face, in cells that are specialised for secretion

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46
Q

What are the functions of the golgi complex?

A

glycosylation of proteins (add/modify of carbos to proteins, imp for cell surface proteins), synthesis of many polysaccharides that are secreted, sorting proteins, directing vesicle trafficking

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47
Q

What is constitutive exocytosis?

A

continuous/unregulated, e.g. Extracellular matrix proteins

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48
Q

What is regulated exocytosis?

A

regulated/in response to stimulus e.g. hormones and neurotransmitters

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49
Q

What is phagocytosis?

A

transport of large particulate substances into the cell, forms a phagocytic vacuole around it, cell eating, non selective

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50
Q

What is pinocytosis?

A

uptake of Extracellular fluid and solutes, uptake is non selective, cell drinking

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51
Q

What is receptor mediated Endocytosis?

A

Specialised type of pinocytosis, take up specific molecules which are often in low concentration outside of the cell (cholesterol), receptors on cell surface bind to specific molecules, selective

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52
Q

What are lysosomes made by? And what type of enzymes do they contain

A

rER and Golgi body, contain hydrolytic enzymes

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53
Q

What is the functions of a lysosome?

A

they degrade proteins, lipids, carbohydrates and nucleic acids and release breakdown products into the cell, digest and recycle unwanted cellular materials (autophagy)

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54
Q

What is the cytoskeleton and what is its function?

A

3-dimensional interconnected network within a cell and provides structure, important role in cell movement and transport, 3 components are microtubules, microfilaments, intermediate filaments

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55
Q

Microtubules

A

form a tube, composed of tubular subunits, resist compression, can be dismantles and reassembled, provides cell motility, example of motility is flagella, allow things to be transported to specific targets

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56
Q

Microfilaments

A

double chain of actin subunits, resist tension, forms linear strands and 3-d networks, actin and myosin interactions

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57
Q

Intermediate filaments

A

made of various proteins like keratin, bearing tension, help shape and ancho some organelles, make up the nuclear lamina

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58
Q

Tight Junctions

A

Prevent movement of fluid between cells, neighbouring cells are tightly pressed together and held by proteins, form continuous seal

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59
Q

Gap Junctions

A

Communication between cells, point of cytoplasmic contact between 2 cells, ions and molecules can pass cell to cell, rapid communication

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60
Q

Desmosomes

A

Anchor and hold cells together, interacting with intermediate filaments, act like rivets, anchoring junctions, intermediate filaments anchor desmosomes to the cytoplasm

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61
Q

Collagen in the ECM

A

Most abundant glycoprotein, strong fibres, great tensile strength

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62
Q

What do fibronectins and integrins do?

A

attach cells to collagen in the ECM (Fibronectins), provide a communication link, connect ECM to cytoskeleton (integrins)

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63
Q

is there a ECM in plant cells?

A

no, cells held together by middle lamella (pectin), intercellular communication via plasmodesmata

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64
Q

What is a protoplast?

A

all of the cell structures inside the cell wall

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65
Q

Order of cell wall structure

A

Plasma membrane, secondary cell wall, primary cell wall, middle lamina

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66
Q

Phase 1 of synthesis of the primary cell wall

A

Crystalline microfibrillar phase, synthesised at the plasma membrane by an enzyme called cellulose synthase

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67
Q

Phase 2 of synthesis of the primary cell wall

A

Non crystalline matrix - hemicellulose and pectin synthesises in the golgi by constitutive exocystosis, extensin synthesised in rER

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68
Q

How does the cell wall regulate shape?

A

influences cell morphology, provides structural support (protoplast), prevents excessive water uptake

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69
Q

What is the secondary cell wall made of?

A

more cellulose, less pectin and lignin (complex polymer). And microfibrils in each layer have different orientations

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70
Q

What is the vacuoles function?

A

regulation of turgor

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71
Q

What is the process of energy generation?

A

cellular respiration

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72
Q

What does the mitochondrion contain?

A

mitochondrial DNA and ribosomes, it is semi-autonomous, 2 membranes

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73
Q

What are the 3 main stages of cellular respiration? And where do they occur?

A
  1. Glycolysis in the cytosol 2. Citric acid cycle in the mitochondrial matrix 3. Oxidative phosphorylation in the inter membrane space across the inner membrane
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74
Q

What happens during glycolysis (stage 1) and what does it generate?

A

glucose is converted into 2 smaller molecules of pyruvate. Generates ATP and electrons are transferred to high energy carrier NAD+ making NADH

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75
Q

What happens during pyruvate oxidation and citric acid cycle (Stage 2) and what are the outputs?

A

Pyruvate is converted into Acetyl CoA and that enters the citric cycle and is further processed into CO2, other outputs are ATP and NADH and FADH2

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76
Q

What happens in the first part of Oxidative phosphorylation (stage 3) and what are the outputs?

A

ETC, electron carriers shuttle high energy electrons to inner mito membrane, they move along proteins embedded in the inner membrane, as they move protons H+ are pumped across the inner membrane to the inter membrane space, proton gradient formed

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77
Q

What happens during chemiosmosis (part 2 of oxidative phosphorylation stage 3) and what does it generate?

A

Inner mitochondrial membrane contains ATP synthase, protons move down concentration gradient though this, powers ATP synthase, generates ATP

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78
Q

What are the 3 membranes and 3 compartments in a chloroplast?

A

membranes - outer, inner, thylakoid. Compartments - intermembrane space, stroma, thylakoid space

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79
Q

Where do light reactions take place?

A

thylakoid membrane

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80
Q

Where does carbon fixation occur?

A

stroma

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81
Q

What is the purpose of the light reactions? And what proteins does it use?

A

produce ATP and NADPH for the Calvin cycle, uses specialised membrane proteins called photo systems

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82
Q

What are photosystems?

A

pigment protein complexes that are found in the thylakoid membrane, contain chlorophyll, there are 2 photosystems (ll is for water splitting and l is for NADPH producing) (connected by ETC)

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83
Q

What does photosystem ll provide a source of?

A

electrons, H+ ions, O2, electrons form this move into photosystem l

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84
Q

What does the Calvin cycle use and produce?

A

uses ATP and NADPH from light reactions, produces 3 carbon sugar (G3P) that is converted to glucose, also referred to as light independent reactions, ‘fix’ carbon

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85
Q

How do molecules move in and out of the nucleus?

A

small molecules (ions) diffuse through, large molecules (proteins) are actively transported

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86
Q

What does the nuclear pore complex control?

A

movement of molecules in or into the nucleus. OUT - mRNA, tRNA, and ribosomal subunits IN controls signals, building materials and energy like when to turn a gene on or off

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87
Q

What does mRNA do?

A

carries information from a gene to a ribosome in the cytoplasm

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88
Q

What is the inner surface of the nuclear envelope lined by and what is it composed of and helps to do?

A

nuclear lamina, intermediate filaments, helps maintain shape of nucleus and helps organise the packing of DNA

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89
Q

When is the nucleolus visible and what does it make?

A

during interphase and is a ribosome factory, makes large and small sub units of the ribosomes

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90
Q

Heterochromatin

A

densely packed, genetically inactive

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91
Q

Euchromatin

A

not as dense, genetically active

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92
Q

Endosymbiont theory steps

A
  1. Large felled prokaryote (host)
  2. In folding of plasma membrane forming internal compartments
  3. Large host cel engulfed an aerobic prokaryote
  4. Eventually the aerobic prokaryote evolved into a semi autonomous organelle - mitochondrion
  5. Large host cell engulfed a photosynthetic prokaryote
  6. Eventually the photosynthetic prokaryote evolved into a semi-autonomous organelle - chloroplast
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93
Q

Evidence of the endosymbiont theory

A

all eukaryotes have mitochondria, only plants and some protists have chloroplasts, characteristics of mito and chloroplast suggest the were one free living prokaryotic organisms (semi autonomous, have 2 membranes surrounding them, similar size to prokaryote, contain “prokaryote like” ribosomes and DNA and they divide by binary fission

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94
Q

What are the 3 key features of a hereditary molecule?

A

encodes and stores information, mechanism for replication, transmissible

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95
Q

How are nucleotide units linked together?

A

through the phosphate groups, forming the backbone of the molecule, phosphodiester bonds

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96
Q

What are purines?

A

nitrogenous bases, double ring structure, A and G

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97
Q

What are pyrimidines?

A

nitrogenous bases, single ring structure, C U and T

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98
Q

What end is the phosphate group attached to?

A

carbon 5 (5’ carbon)

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99
Q

What is the OH group attached to?

A

carbon 3 (3’ carbon)

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100
Q

Explain the steps of replication

A

helicase unwinds, Enzyme called primase attaches an RNA primer (short sequence of RNA nucleotides) then DNA pol lll attaches, it joins new nucleotide to newly synthesised strand of DNA in the 5’ to 3’ direction, DNA pol l removed RNA primer, DNA ligase seals the gap.

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101
Q

What binds to a strand to stop it from winding back together?

A

Single-strand binding protein

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102
Q

What does topoisomerase do?

A

cut and rejoin double stranded DNA ahead of the replication fork and relieves pressure caused as the strands unwind

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103
Q

What does mitosis and meiosis produce?

A

mitosis - genetically identical somatic cells used for growth and repair
Meiosis - produces genetically distinct gametes for sexual reproduction

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104
Q

Definition of diploid cell

A

Cells that contain pairs of homologous chromosomes

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105
Q

Definition of haploid

A

Cells that contain one copy of each chromosome (no pairs)

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106
Q

Explain interphase

A

Longest part of cell cycle
G1 - cells grow and produce proteins and organelles
S - synthesis phase, DNA replication occurs, chromosomes replicate
G2 - cells prepare for cell division

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107
Q

What does everything look like at the end of interphase?

A

DNA/chromosomes are replicated but not condensed, nuclear envelope is present, nucleolus is visible, centrosomes have duplicated

108
Q

Describe prophase of mitosis

A

replicated chromosomes begin to condense, centrosomes move to opposite poles and form spindle, single microtubules attach to the centromere of each replicated chromosome, nuclear membrane breaks down

109
Q

Describe the 2 types of mitotic spindles

A

Kinetochore microtubules - attach to the kinetochore proteins at the centromere of each chromosomes
Nonkinetochore microtubules - do not attach to chromosomes, they elongate during anaphase

110
Q

Describe metaphase in mitosis

A

Spindle microtubules are fully formed, replicated chromosomes move to the centre of the cell, centromeres lie on the metaphase plate

111
Q

Describe anaphase in mitosis

A

Kinetochore microtubules retract and seperate the sister chromatids, chromosomes move to opposite ends of poles, cell elongates due to nonkinetochore microtubules

112
Q

Describe telophase of mitosis

A

nuclear envelope beings to form at either end of the cell, chromosomes start to decondense (unwind), spindle disappears, nucleolus reappears

113
Q

Describe cytokinesis of mitosis

A

Cytoplasm divides between the 2 cells

114
Q

Definition of a karyotype

A

ordered, visual representation of the pairs of chromosomes in a cell

115
Q

What happens during prophase 1 meiosis 1?

A

Chromosomes begin to condense, homologous pairs of chromosomes pair up (synapse), crossing over occurs

116
Q

What happens during metaphase 1 meiosis 1?

A

pairs of homologous chromosomes move to metaphase plate, chiasmata align along the plate, chromosomes are attached to the microtubules attached to the centromere.

117
Q

What happens during anaphase meiosis 1?

A

homologous pairs of chromosomes are separated, each replicated chromosome moves to opposite poles of the cell

118
Q

What happens during telophase and cytokinesis meiosis 1?

A

Go to each pole, spindle disappears and nuclear envelope reforms, then cytokinesis

119
Q

What does everything look like at the end of meiosis 1?

A

resulting cells contain one copy of each chromosome, haploid, cells are genetically different

120
Q

What does everything look like at the end of meiosis ll?

A

4 cells, each cell contains one copy of each chromosome, haploid, genetically different

121
Q

What does non-disjunction during meiosis l anaphase 1 result in?

A

n+1, n+1, n-1, n-1

122
Q

What does non-disjunction during meiosis ll result in?

A

n+1, n-1, n, n

123
Q

what is gene dosage?

A

number of copies of a particular gene present in a cell of an organism

124
Q

What is the definition of deletion?

A

loss of a part of a chromosome, affected chromosome is then missing certain genes, deletion affect the number of copies of the gene involved

125
Q

What is the definition of duplication in regard to chromosomal rearrangements?

A

segment is repeated

126
Q

What is the definition of inversion in regard to chromosomal rearrangements?

A

segment of chromosome is detached and then reattached in opposite orientation, affects gene expressions and regulation

127
Q

What is the definition of translocation in regard to chromosomal rearrangements?

A

segment of one chromosome attaches to another non-homologous chromosome, swap fragments

128
Q

General outline transcription

A

It is the synthesis of messages RNA, RNA polymerase synthesises mRNA by catalysing the formation of phosphodiester bonds between ribonucletides, selects the correct nucleotides to incorporate into mRNA based on the sequence being transcribed, transcribes from the template strand

129
Q

Outline initiation of transcription

A

binding of RNA polymerase to transcription factors at the promoter region TATA, unwinding of DNA, reading of the template strand and starting the synthesis of the RNA strand

130
Q

Outline elongation of transcription

A

RNA pol used the template strand as a template and inserts complementary RNA nucleotides

131
Q

Outline the termination sequence of transcription

A

terminates RNA synthesis, RNA polymerase detached from DNA strand and RNA strand is released

132
Q

What happens to mRNA before it leaves the nucleus for transcription ?

A

addition of 5’ G cap and Poly-A tail, splicing of introns

133
Q

What is translation?

A

synthesis of proteins by ribosomes using mRNA as a set of instructions

134
Q

What is tRNA?

A

‘Adaptor’ molecule, each one has a region that can bind an amino acid and a region which can interact with mRNA, when bound to a tRNA it is charges

135
Q

Outline initiation in regard to translation

A

5’ end of the mRNA binds to the small ribosomal subunit at a specific sequence, ensures mRNA is in the right frame to be read, large ribosomal subunit attaches

136
Q

Outline elongation in regard to translation

A

charged tRNA with the anticodon that matches the next codon on the mRNA binds to the A site of the ribosome, ensures correct amino acid is brought into frame, ribosome catalyses the formation of peptide bonds, ribosome breaks bond between polypeptide chain in the P site and joint it to the amino acid in the A site, tRNA in P site is now uncharged

137
Q

Outline termination in regard to translation

A

Stop codons are coded for by proteins (release factors) not tRNA, when it bind the ribosome separates and releases mRNA and polypeptide chain, it goes on to form protein

138
Q

Definition of a gene

A

Unit of heredity, codes for a specific trait

139
Q

What is Mendels first law?

A

the law of segregation - genes seperate at meiosis so that each gamete contains only one of the two possessed by the parent

140
Q

What is Mendels second law?

A

The law of independent assortment - alleles of different genes assort independently during gamete formation

141
Q

What is the phenotypic cross of a mono hybrid ratio?

A

3:1

142
Q

What is the phenotypic cross of a dihybrid ratio?

A

9:3:3:1

143
Q

How do you calculate the probability of parents producing a specific genotype?

A

Do a small punnet square of each letter, if its 2/4 it will be 0.5, after getting them all then times them together

144
Q

What are the 3 ways there could be a deviation from Mendel? With brief explanations

A

Polymorphic genes - one gene having many alleles
Incomplete dominance - like a white and red flower making a pink flower
Co-dominance - 2 alleles affect genotype in seperate ways

145
Q

What is polygenic inheritance?

A

When many genes affect one trait, like skin colour

146
Q

What is a autosome?

A

all other chromosomes that aren’t sex linked genes

147
Q

What do most genes on the Y chromosome control?

A

characteristics related to determining sex

148
Q

Fathers can pass X-linked genes on to? And mother can pass X-linked genes on to?

A

fathers- only daughters
Mothers - sons and daughters

149
Q

If a disease is X-linked dominant who can express the disease?

A

males and females

150
Q

If a disease is X-linked recessive who can express the disease?

A

all males, only females if they carry 2 copies of the disease causing allele

151
Q

If a female has an X-linked dominant disease she will pass her affected X chromosome on to what percent of her children?

A

50% regardless of sex

152
Q

If a female has an X-linked recessive disease she will pass an affected X chromosome onto what percent of her children?

A

100%

153
Q

What X linked diseases (dominant or recessive) are more common in which gender? And who does Y-linked diseases affect?

A

X-linked dominant is more common in females, X-linked recessive is more common in males, Y-linked is rare and only affects males

154
Q

What ratio will a dihybrid individual produce 4 gametes at?

A

1:1:1:1

155
Q

In what situation could a gene not assort independently?

A

if they are on the same chromosome

156
Q

What is complete linkage? And what outcome is the ratio?

A

when 2 genes are very close together on the same chromosome and crossing over does not occur between them, 1:1

157
Q

What is incomplete linkage? And what outcome is the ratio?

A

2 genes on the same chromosome and crossing over occasionally happens between them, unequal ratios because more parental than recombinant types

158
Q

What is the measure of distance between 2 genes? And how do you calculate the recombination frequency?

A

Centrimorgans which is recomb freq X 100, recomb freq = # of recombinant divided by total # of offspring

159
Q

Definition of a population

A

a group of interbreeding individual of the same species in the same location that produce fertile offspring

160
Q

Definition of a gene pool

A

The sum of all the alleles, at every locus on every chromosome, in all members of a population, at one time

161
Q

What does it mean if a allele is fixed?

A

there is only one allele for a gene in a population, all individuals will be homozygous for that allele

162
Q

What does the Hardy-Weinburg principle state and what can it be used to determine?

A

that frequencies of alleles and genotypes in a population will remain constant from generation to generation, can be used to determine in natural selection or other factors are causing changes of allele frequencies in a population

163
Q

What 2 reason why we might need to estimate frequencies of genotypes in a population?

A
  1. To predict how many individuals will inherit a genetic disease
  2. To estimate the proportion of individuals who are carriers of a genetic disease
164
Q

How do allele frequencies change?

A

genetic drift (3 types), gene flow or migration, natural selection, non random mating, mutation

165
Q

What is random genetic drift?

A

a random change in allele frequencies over generations due to change events

166
Q

What is the bottleneck effect?

A

occurs when a population has reduced dramatically as a result of natural disaster, disease or human actions, reduce genetic diversity so resulting allele frequencies are not representative of original population

167
Q

What is the founder effect?

A

When a few individuals of a larger population become founders of anew population

168
Q

What 4 things do you require for natural selection?

A

variance, inheritance, selection, time

169
Q

What is stabilising selection?

A

selection against both extremes, graph os one peak in the middle, reduced variation but does not change the mean

170
Q

What is directional selection?

A

changes the mean towards one extreme, graph is towards one side

171
Q

What is disruptive selection?

A

Favours the 2 extremes, results in 2 peaks

172
Q

What is frequency dependant selection?

A

A type of natural selection where the fitness of a phenotype depends on the frequency of that phenotype in the population

173
Q

Outline what a phylogenetic tree is

A

Represents a hypothesis about the evolutionary relationships, characteristics shared between organisms are used, physical or DNA

174
Q

What is a genome?

A

the complete set of DNA of an organism including all of its genes, includes nuclear and mitochondrial DNA

175
Q

What is a SNP?

A

single nucleotide polymorphism, most common type of genetic variation in humans, most don’t do anything and are just inherited variations, can be outside or inside a gene

176
Q

What is a STR?

A

repeats of 2-5 nucleotides found in specific regions of the genome

177
Q

What are InDels?

A

second most common variant type in human genome (cystic fibrosis), can cause frame shifts (changes entire DNA sequence after the mutation)

178
Q

What is CNVs?

A

Copy number variants, chunks of DNA that are present a variable number of times in different people

179
Q

What are things in common when comparing genomes called?

A

conserved

180
Q

What are mutations called that are inherited and passed on via gametes?

A

germline mutations

181
Q

Is a loss of function mutation recessive or dominant and why?

A

often recessive, a normal copy exists on the other chromosome and replaces the lost function

182
Q

Is a gain of function mutation recessive or dominant and why?

A

often dominant, effect of the gain of function in not masked by the normal copy on the other chromosome

183
Q

Do dominant diseases skip generations?

A

no

184
Q

Do recessive diseases skip generations?

A

They can

185
Q

What is an example of a autosomal dominant disease?

A

huntingtons disease

186
Q

Do autosomal diseases affect males or females more?

A

Affects them equally

187
Q

Difference between monogenic and polygenic diseases?

A

Monogenic diseases are caused by a single gene, polygenic diseases are caused by multiple genes and can also be affected by the environment

188
Q

How do you use CRISPR-CAS9 to edit genes?

A

cas9 enters the nucleus and finds target sequence in genome that matches the guide RNA, after DNA is cut there is 2 options, 1. If no DNA repair template in provided DNA repair enzymes will try to patch up the cut which often results in errors and small InDels are created at the target site, 2. If a DNA repair template is provided it can be used to ‘edit’ the DNA sequence at this cut sight

189
Q

What are the 3 ways to find out what a gene does?

A

study mutations, trangenesis, deliberately break a gene and see what happens (gene knockout, like using CRISPR-Cas9 without a template), all these are called functional molecular genetics

190
Q

Can we fix genetic disease?

A

yes, but only if we know what causes it and have a way to correct the defect, best candidate are single gene disorders and using gene therapy like gene editing

191
Q

What is differentiation?

A

the process by which a cell becomes specialised in structure and function

192
Q

An embryo begins as a small number of ? Cells? Give definition too

A

Totipotent, unspecialised cells with total potential - can develop into all cells of the embryo and the placenta

193
Q

At the blastocyst stage we see 2 types of cells. The outer cells become ? And the inner mass cells are ?

A

outer - placenta
Inner - embryonic stem cells (pluripotent)

194
Q

embryonic stem cells are still ? And can give rise to ?

A

unspecialised and give rise to all cell types except the placenta

195
Q

When differentiated cells divide by mitosis they can only ?

A

divide to become the same type of cell

196
Q

Control genes make proteins called ? That ‘switch on” other genes in the cell

A

Transcription factors

197
Q

What does switching on a gene mean?

A

that it is transcribed into RNA and then translated to make proteins, once its on its fate has become determined

198
Q

Why are stem cells different?

A

Can divide without limit, undifferentiated, give rise to both stem cells and cells which will go on to differentiate into functional tissue cells

199
Q

Are embryonic stem cells multi potent or pluripotent ?

A

human ones are pluripotent

200
Q

Are adult (tissue) stem cells multi potent or pluripotent ?

A

multi potent

201
Q

Blood stem cells or haematopoiteic stem cells are what type of stem cells?

A

adult, important for tissues and used for transplants

202
Q

What are iPS cells?

A

induced pluripotent stem cells, genetically identical to source skin cells, as they are pluripotent they can be cultures to generate into any cell type

203
Q

Prokaryotic cells are characterised by what 4 things?

A

unicellular, no nucleus, no membrane bound organelles, small size

204
Q

What is the 2 functions of the bacterial cell wall?

A

rigid structure that provides strength to cell maintaining shape, provides physical protection (prevents cell losing/bursting due to osmotic stress)

205
Q

What is transpeptidase?

A

enzyme that cross links the peptidoglycan chains to form rigid cell walls

206
Q

Is the layer of peptidoglycan around gram positive bacteria thick or thin, and what colour is the gram stain?

A

thick, positive which is purple

207
Q

Is the layer of peptidoglycan around gram negative bacteria thick or thin, and what colour is the gram stain?

A

thin, negative which is pink

208
Q

What is the function of glycocalyx?

A

Prevents desiccation, and allows adhesion, in pathogenic bacteria it can help the cell avoid the hosts immune system and it increases resistance to phagocytosis

209
Q

What is the structure and function of fimbriae?

A

Short, sticky and made of protein, shorter than flagella, function is adhesion and joining cells together to form biofilms, like Velcro

210
Q

What is the structure and function of Pili?

A

filamentous projections from surface of cell made of protein, longer than fimbriae and shorter than flagella, involved in conjugation, 1-10 per cell

211
Q

What is the nucleoid region?

A

location of bacterial chromosome which is a single large loop of DNA associated with proteins

212
Q

What is a plasmid and what is its function?

A

short circular loop of DNA, can carry resistance genes and are involved in gene transfer via a pilus

213
Q

What is the structure and function of a endospore?

A

original cell makes a copy of chromosome and surrounds it in a tough cell wall and metabolism stops, very resistant cells produced during adverse condition e.g. lack of nutrients, allows DNA to resist things

214
Q

What are the 4 steps of binary fission?

A
  1. Chromosome replication begins
  2. One copy of the origin is now at each end of the cell
  3. Replication finishes
  4. 2 daughter cells result
215
Q

What are the 3 things needed for microbial growth ?

A

energy source, carbon source, reducing power

216
Q

What is cryptic growth?

A

when organisms survive by consuming components of other dead cells within a culture

217
Q

What is an auxotroph?

A

species that lack one or more essential genes and therefore cannot grow unless that specific factor is supplied

218
Q

How do auxotrophs survive in nature?

A

by cross feeding which is when one species gains the metabolic products of another species

219
Q

What is the definition of a microbiome?

A

the complete collection of microorganisms, and their genes, within a particular environment

220
Q

Pros and cons of culture dependant approaches?

A

pros - can study phenotype, can manipulate the culture conditions to see response of organism
Cons - many species can’t be cultured, too many to try and culture, doesn’t match real world conditions

221
Q

Pros and cons of culture independent approaches?

A

Pros - study many organisms at once to build a picture of their communities, provides genotype
Cons - provides no information on how they grow and condition required, expensive and complex methods

222
Q

Why do bacteria need an energy source to grow?

A

needs ATP for catabolic and anabolic reactions, catabolic reactions breaks large molecules into smaller molecules and therefore release energy, anabolic reaction synthesis large molecules from small molecules and therefore us energy

223
Q

Why do bacteria need a carbon source to grow?

A

needs to be able to generate macromolecules and therefore needs building blocks, can be organic or inorganic

224
Q

Why does bacteria need reducing power to grow?

A

needs carriers of electrons NAD+/NADP+, for redox reaction

225
Q

What makes something a auto or hetero troph?

A

autotroph uses a carbon source - inorganic/CO2 and a heterotroph does not

226
Q

Definition of microbiota

A

Individual microbial species in a biome

227
Q

What are the 4 phyla that dominate the human microbial communities ?

A

firmicutes, bacteroidetes, actinobacteria, proteobacteria

228
Q

What are some known functions of the human microbiome?

A

priming the immune system, moderating energy intake, synthesis of compounds such as vitamins

229
Q

Definition of probiotics?

A

live microorganisms

230
Q

Definition of prebiotics?

A

an ingredient that beneficially nourishes the food bacteria already in the large bowel or colon, stimulate growth of probiotics, fertiliser

231
Q

Viruses are referred to as? And why?

A

particles or acellular R obligate parasites because they do not have ribosomes, a plasma membrane or cytosol

232
Q

All viruses consist of?

A

nucleic acid and a capsid which provides protection and is made up of subunits called capsomeres

233
Q

What are the 4 categories for classification of viruses?

A

type of nucleic acid, presence or absence of envelope, capsid symmetry/shape, target host

234
Q

What are the 3 types of symmetry of viruses?

A

helical, icosahedral, complex

235
Q

List the 6 steps of viral infection

A
  1. Attach - to receptor proteins on cell surface
  2. Penetrate
  3. Uncoat - capsid uncoats
  4. Gene expression and genome replication - uses host cell enzymes to synthesis
  5. Assembly - new virus particles assemble
  6. Release - from the cell
236
Q

Morphology of bacteriophages

A

head - capsid and nucleic acid
Tail - attached to receptor proteins on bacterial wall and acts like a hypodermic needle to puncture through

237
Q

What viruses are eukaryotic cells infected by?

A

naked or enveloped viruses

238
Q

Vertical gene transfer

A

between generations, in prokaryotes this is via binary fission, creates genetic diversity

239
Q

Horizontal gene transfer

A

from one bacteria to another within same generation, transformation, transduction, conjugation, generates genetic diversity

240
Q

What is transformation in regard to generating genetic diversity?

A

competent cells take up DNA from environment, DNA binding proteins on their surface allows the cell to be selective about what DNA it takes up, if it integrates the DNA it becomes a recombinant cell

241
Q

What is transduction in regard to generating genetic diversity?

A

transfer of bacterial DNA carried from one host cell to another by bacteriophages, remember that bacteriophages infect bacteria, same general process as Lytic cycle, creates a transducting phage

242
Q

What is conjugation in regard to generating genetic transfer?

A

direct transfer of plasmid DNA between 2 cells that are temporarily joined by a conjugation pilus

243
Q

What features can be transferred via horizontal gene transfer?

A

virulence factors, antibiotic resistance

244
Q

What are Koch’s postulates criteria ? (4)

A
  1. The organism must be present in every case of the disease
  2. The organism must be isolated from the host with the disease and grown in pure culture
  3. The specific disease must be reproduced when a pure culture of organisms are inoculated into a healthy host
  4. The organisms must be recoverable from the experimentally infected host after disease develops
245
Q

What are the exceptions to Koch’s postulates criteria ? (4)

A
  1. Some organisms cannot be isolated and cultured under laboratory conditions
  2. Some disease are due to a combination of organisms
  3. Some pathogens are found in healthy hosts
  4. Some carriers are asymptomatic
246
Q

What are 3 medically important pathogens and examples?

A

viruses (influenza), Protozoa (malaria parasites), bacteria (anthrax)

247
Q

What are the 4 key stages to microbial pathogenesis (disease development)?

A
  1. Adherence to host - e.g. fimbriae and adhesions
  2. Invasion of host tissues - e.g. flagella
  3. Replication within host tissues - e.g. capsule, siderphores
  4. Disease causing damage to host tissues - e.g. exotoxins and endotoxins
248
Q

What is virulence ?

A

a measure of ability of a microbe to infect and cause disease, does not relate to severity of disease

249
Q

Why do not all bacteria have the same level of virulence and what is it called when they cannot attach to the host?

A

due to their ability to produce virulence factors which increase the virulence of a pathogen, avirulent

250
Q

Name virulence factors and what they do?

A

adhesions - allow microorganisms to attach, motility (chemotaxis) - some pathogens with flagella can move through mucus and therefore invade host cells, capsules (glycocalyx) - polysaccharide coating around cells which prevents phagocytosis by host immune cells, siderophores - iron binding proteins allow pathogens to remove iron from the blood stream and transport it to their own cells, endotoxins - lipopolysaccharides, exotoxins

251
Q

What are the 3 targets of exotoxins?

A

cytotoxins, neurotoxins, enterotoxins

252
Q

What is selective toxicity?

A

more toxic to pathogen that to its host and therefore target structural or metabolic differences between microorganism and host cell

253
Q

Definition of an antibiotic

A

antibacterial agent including naturally and synthetically produced compounds excluding agents with antiviral and anti fungal activity, selectively toxic

254
Q

Difference between antibacterial and antimicrobial?

A

antibacterial is only against bacteria, antimicrobials act gains bacteria, virus, fungi and protozoa

255
Q

How does penicillin work?

A

acts by preventing the formation of peptide cross links in the cell wall by binding to and inhibiting the enzyme transpeptidase

256
Q

How does penicillin resistance happen?

A

some bacteria produce an enzyme which degrades/breaks down penicillin by targeting the B-lactam ring, called penicillinase or B-lactamase, breaks the bond

257
Q

How does antibiotic resistance occur? General and the 4 steps

A

original change arises from a mutation, if it’s beneficial it will be selected for, resistance genes can spread from one cell to another by horizontal gene transfer
1. Some bacteria in the human body become drug resistant
2. Antibiotics kill bacteria but not those resistant to drugs
3. Resistant bacteria then have space to multiply
4. Bacteria can transfer their drug resistance to other bacteria

258
Q

How do you prevent antibiotic resistance occurring? (4)

A

decrease utilisation, improve diagnostics, identify new targets, combination therapys

259
Q

Describe the 5 stages of an infectious disease?

A
  1. Incubation period - time between infections and occurrence of first symptoms, pathogen attaches and beings to replicate, length of this stage depends on virulence, immune response, sit of infection
  2. Prodromal period - as pathogen levels being to increase general symptoms are seen, a short period of mild symptoms that occur before illness
  3. Illness - characteristic symptoms of illness, most severe stage, immune responses not yet helpful, most infectious stage, highest concentration of pathogen
  4. Decline - immune response or medical treatment starts to decrease pathogen numbers, symptoms lessen
  5. Convalescence - recovery, tissue repairs, length depends on amount of tissue damages, nature of pathogen, infection site, patient health, and there’s a low level of pathogen
260
Q

What are the 6 steps of the chain of infection?

A
  1. Causative pathogen - what pathogen is causing the disease like virus bacteria parasite
  2. Source where pathogen is found
  3. Means for exiting the source and therefore infection another host
  4. Mode of transmission
  5. Entry point (way into host body)
  6. Host that is at risk of infection
    All comments must be present for infection to spread
261
Q

What is epidemiology?

A

the study of disease transmission

262
Q

What is the incidence of a disease?

A

the number of new cases of the disease in a given period of time

263
Q

What is the prevalence of a disease?

A

the total number of new and existing cases in a population in a given time

264
Q

Endemic

A

always present at stable levels within a given population or area

265
Q

Sporadic

A

a disease that occurs infrequently and irregularly

266
Q

Epidemic

A

an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area

267
Q

Pandemic

A

An epidemic that has spread over several countries or continents, usually affecting a large number of people

BIOL112 (3 decks)

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