IB Biology: Level 9 - Intro to Molecular Biology 2.1 Flashcards

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1
Q

Outline what molecular biology is and what it explains

A
  • explains living processes in terms of the molecules involved
  • reductionist approach
  • to work out the structure of organic molecules which make up living things
  • e.g. DNA, RNA, proteins, carbohydrates, lipids
  • understanding structure leads to understanding function
  • how molecules interact with each other;
    biochemical pathways to form new substances and break down others
  • perhaps cannot yet explain emergent properties when all molecules are combined
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2
Q

Explain how the synthesis of urea falsifies vitalism

A
  • vitalism stated that living molecules cannot be made artificially
  • urea discovered in 1720s in urine
  • nitrogen containing compound
  • waste product of protein breakdown
  • however, was artificially synthesized in 1800s
  • therefore, organic molecules from living things can be synthesized artificially
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3
Q

Explain how carbon can lead to diversity of compounds

A
  • carbon can form 4 covalent bonds;
  • therefore can become the backbone of molecules
  • form chains
  • ring structures
  • link together
  • form double bonds with itself
  • can bond with just one atom like hydrogen, or multiple different ones
  • giving a huge range of properties for organic molecules in living things
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4
Q

State the most frequently occurring chemical elements in living things

A

Most common in living organisms are Carbon, Hydrogen and Oxygen, then nitrogen. Carbon COxygen, OHydrogen, HNitrogen, N

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5
Q

State that a variety of other elements are needed by living organisms (other than C,H,O,N,S)

A

Living organisms require CHONS plus calcium, phosphorus, iron and sodium and other elements

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6
Q

Describe the classifications of carbon compounds that life is based on

A

Carbohydrates:
- Composed of carbon, hydrogen and oxygen
-ratio of 2 hydrogen to one oxygen atom
- hence the name carbohydrate

Lipids:
- broad class of molecules that are insoluble in water
- including steroids, waxes, fatty acids, triglycerides
- mainly made of carbon, hydrogen and oxygen, though not a fixed ratio
- often in long chains
- e.g. fatty acids
or ring shapes
- e.g. steroids

Proteins:
- made of one or more chains of amino acids
- contain carbon, hydrogen, oxygen, nitrogen and sulphur (only 2 of twenty);
Nucleic acids- subunit called a nucleotide
- contain carbon, hydrogen, oxygen, nitrogen and phosphorous
- two types, RNA (single stranded) and DNA (double stranded)

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7
Q

Draw a diagram of alpha D-glucose (or explain what it looks like verbally)

A
  • Ring structure
  • but! 6th member of the ring is actually oxygen in top right
    carbon 3 has OH sticking up, all others are sticking down
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8
Q

Draw a diagram of beta D-glucose (or explain what it looks like verbally)

A

Same as alpha BUT has 1st carbon OH group going down, as well as carbon 3

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9
Q

Draw a diagram of ribose (or explain what it looks like verbally)

A
  • 5 carbon molecule
  • pentagon shape
  • oxygen is a top, not carbon
  • formula is C5 H10 O5
  • OHs for 1 and 5 point up, 2 and 3 point down
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10
Q

Draw a diagram of a saturated fatty acid (or explain what it looks like verbally)

A
  • Long chain of C and H, acid group at end with COOH structure
  • no polar bonds
  • therefore non-polar and hydrophobic
  • e.g. phospholipid tails
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11
Q

Draw a diagram of an amino acid (or explain what it looks like verbally)

A
  • NH2 group at one end, COOH group at other
  • R group (which is actually usually C and other atoms) at top
  • meaning variable group (could be CH3, could be CH2CH3, depending on the amino acid)
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12
Q

Outline metabolism

A
  • the web of enzyme catalyzed reactions - sum of all the reactions
  • most take place in cytoplasm
    -involve many steps
  • eg. A-B-C-D, where each step is catalyzed by a different enzyme
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13
Q

Outline anabolism

A
  • synthesis of complex molecules
  • from simpler ones
  • e.g. protein synthesis from amino acids
  • DNA from nucleotides
  • photosynthesis of glucose from water and carbon dioxide
  • starch from glucose
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14
Q

Outline catabolism

A
  • breakdown of large complex molecules into simpler ones
  • release energy
  • which can be captured in the form of ATP
  • e.g. cell respiration where glucose is broken down
  • digestion of starch into glucose molecules
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