2.1 Flashcards

1
Q

Molecular biology

A

Molecular biology is a field of study that focuses on investigating biological activity at a molecular level

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2
Q

Molecular Biology includes…

A

elucidating the structure and function of chemical substances and determining their interactions as parts of living processes

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3
Q

Biological processes are regulated by

A

by enzymes, whose expression is controlled by gene activation (DNA)

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4
Q

changes in activity

A

Changes in activity are typically determined by signalling molecules (either endogenous or exogenous in origin)

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5
Q

organic compounds

A

An organic compound is a compound that contains carbon and is found in living things

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6
Q

organic compound exceptions

A

Exceptions include carbides (e.g. CaC2), carbonates (CO32–), oxides of carbon (CO, CO2) and cyanides (CN–)

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7
Q

carbon

A
  • Carbon forms the basis of organic life due to its ability to form large and complex molecules via covalent bonding
  • Carbon atoms can form four covalent bonds, with bonds between carbon atoms being particularly stable (catenation)
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8
Q

Main Classes of Carbon Compounds

A

carbohydrates, lipids, nucleic acids, proteins

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9
Q

Carbohydrates

A
  • Most abundant organic compound found in nature, composed primarily of C,H and O atoms in a common ratio – (CH2O)n
  • Principally function as a source of energy (and as a short-term energy storage option)
  • Also important as a recognition molecule (e.g. glycoproteins) and as a structural component (part of DNA / RNA)
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10
Q

Lipids

A
  • Non-polar, hydrophobic molecules which may come in a variety of forms (simple, complex or derived)
  • Lipids serve as a major component of cell membranes (phospholipids and cholesterol)
  • They may be utilised as a long-term energy storage molecule (fats and oils)
  • Also may function as a signalling molecule (steroids)
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11
Q

Nucleic Acids

A
  • Genetic material of all cells and determines the inherited features of an organism
  • DNA functions as a master code for protein assembly, while RNA plays an active role in the manufacturing of proteins
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12
Q

Proteins

A
  • Make over 50% of the dry weight of cells; are composed of C, H, O and N atoms (some may include S)
  • Major regulatory molecules involved in catalysis (all enzymes are proteins)
  • May also function as structural molecules or play a role in cellular signalling (transduction pathways)
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13
Q

macromolecules may commonly be comprised of…

A

smaller, recurring subunits called monomers

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14
Q

what contains monomers?

A

Carbohydrates, nucleic acids and proteins are all comprised of monomeric subunits that join together to form larger polymers

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15
Q

what doesn’t contain monomers?

A

Lipids do not contain recurring monomers, however certain types may be composed of distinct subunits (e.g. triglycerides)

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16
Q

carbohydrate structure

A

Carbohydrates are composed of monomers called monosaccharides (‘single sugar unit’)

  • Monosaccharides are the building blocks of disaccharides (two sugar units) and polysaccharides (many sugar units)
  • Most monosaccharides form ring structures and can exist in different 3D configurations (stereoisomers)
  • structure of complex carbohydrates may vary depending on the composition of monomeric subunits
17
Q

lipid structure

A

Lipids exist as many different classes that vary in structure and hence do not contain a common recurring monomer

  • However several types of lipids (triglycerides, phospholipids, waxes) contain fatty acid chains as part of their overall structure
  • Fatty acids are long chains of hydrocarbons that may or may not contain double bonds (unsaturated vs saturated)
18
Q

protein structure

A

Proteins are composed of monomers called amino acids, which join together to form polypeptide chains

  • Each amino acid consists of a central carbon connected to an amine group (NH2) and an opposing carboxyl group (COOH)
  • A variable group (denoted ‘R’) gives different amino acids different properties (e.g. may be polar or non-polar, etc.)
19
Q

nucleic acid structure

A

Nucleic acids are composed of monomers called nucleotides, which join together to form polynucleotide chains

  • Each nucleotide consists of 3 components – a pentose sugar, a phosphate group and a nitrogenous base
  • The type of sugar and composition of bases differs between DNA and RNA
20
Q

Glucose monomer combinations

A

Glucose monomers can be combined to form a variety of different polymers – including glycogen, cellulose and starch

21
Q

lipid classes

A

Lipids can be roughly organised into one of three main classes:

  • Simple (neutral) lipids – Esters of fatty acids and alcohol (e.g. triglycerides and waxes)
  • Compound lipids – Esters of fatty acids, alcohol and additional groups (e.g. phospholipids and glycolipids)
  • Derived lipids – Substances derived from simple or compound lipids (e.g. steroids and carotenoids)
22
Q

how do amino acids join?

A

Amino acids join together by peptide bonds which form between the amine and carboxyl groups of adjacent amino acids

  • The fusion of two amino acids creates a dipeptide, with further additions resulting in the formation of a polypeptide chain
  • The subsequent folding of the chain depends on the order of amino acids in a sequence (based on chemical properties)
23
Q

how do nucleotides form?

A

Nucleotides form bonds between the pentose sugar and phosphate group to form long polynucleotide chains

  • In DNA, two complementary chains will pair up via hydrogen bonding between nitrogenous bases to form double strands
  • This double stranded molecule may then twist to form a double helical arrangement
24
Q

vitalism

A

Vitalism was a doctrine that dictated that organic molecules could only be synthesised by living systems

  • It was believed that living things possessed a certain “vital force” needed to make organic molecules
  • Hence organic compounds were thought to possess a non-physical element lacking from inorganic molecules
25
how was vitalism disproven
Vitalism as a theory has since been disproven with the discovery that organic molecules can be artificially synthesised - In 1828, Frederick Woehler heated an inorganic salt (ammonium cyanate) and produced urea - Urea is a waste product of nitrogen metabolism and is eliminated by the kidneys in mammals - The artificial synthesis of urea demonstrates that organic molecules are not fundamentally different to inorganic molecules
26
metabolism
Metabolism describes the totality of chemical processes that occur within a living organism in order to maintain life - It is the web of all enzyme-catalysed reactions that occur within a cell or organism
27
metabolism key functions
- They provide a source of energy for cellular processes (growth, reproduction, etc.) - They enable the synthesis and assimilation of new materials for use within the cell
28
anabolism
building up
29
Anabolic reactions describe...
the set of metabolic reactions that build up complex molecules from simpler ones
30
anabolic reactions occur
via condensation reactions | - Condensation reactions occur when monomers are covalently joined and water is produced as a by-product
31
catabolism
breaking down
32
Catabolic reactions describe...
the set of metabolic reactions that break complex molecules down into simpler molecules
33
catabolic reactions occur
via hydrolysis reactions | - Hydrolysis reactions require the consumption of water molecules to break the bonds within the polymer