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LF104: Molecules, Cells And Organisms > 1 - The Molecules of Life - Intro > Flashcards

1 - The Molecules of Life - Intro Flashcards

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Organic Chemistry 101 flashcards
1
Q

What can causes random variation in organisms

A

Random mutation - can change structure and function of protein, etc.

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2
Q

different effects of mutations

A

silent - no effect
small effect, no real advantage or disadvantage
missense or nonsense - disadvantageous
advantageous - very rare, confers selective advantage (prodcues selective pressure)

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3
Q

when did prokaryotes first appear

A

~3500 years ago

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4
Q

5 kingdoms

A

animalia
plantae
fungi
protist
monera

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5
Q

3 domains

A

archaea, eubacteria, eukaryotae

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6
Q

multicellular organisms - levels of interrelationship

A

organ systems
organs
tissues
cells
molecules
- all work together, and coordinated by signalling systems - e.g. cell signalling - enzymes, etc.

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7
Q

which molecules account for moost living matter
- what do they do

A

water
inorganic ions
other small molecules
- usually serve as substrates that for many chemcial reactions inside cells - metabolites - used in metabolism and cell signalling

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8
Q

universal energy molecule

A

ATP - Adenosine Triphosphate
- stores readily available chemical energy in two of its chemical bonds

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9
Q

ATP breakdown products

A

ADP - adenosine diphosphate
inorganic phosphate - Pi/HPO4^2-

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10
Q

use of chemical energy released from ATP bond breaking

A

energy requiring (active) processes
- e.g. muscle contraction, protein biosynthesis

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11
Q

where energy comes from to produce ATP
- example

A

many types of cells break down food molecules which contain chemical energy in their bonds
- sugar broken down, energy in chemical bonds released, captured in energy rich bonds in ATP
- process occurs in most bacteria, animal and plants cells, and other types of cell

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12
Q

Catabolism def

A

breaking of bonds in polymer chains (macromolecules) via hydrolysis reaction to produce monomers (small monomers)

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13
Q

Anabolism def

A

joining of monomers by condensation reaction via ATP to produce polymers

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14
Q

other term for polymer

A

macromolecules

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15
Q

4 macromolecules and monomers

A

polysaccharides - sugars (hexose or pentose)
proteins - amino acids
nucleic acids - nucleotides
lipids - fatty acids

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16
Q

two types of glucose

A

alpha
beta

17
Q

amino acid common chain length in proteins

A

100 - 1000 amino acids

18
Q

some functions of proteins

A
  • enzymes - catalyse cellular reactions involving molecules or macromolecules
  • structural components of cells - e.g. cytoskeleton
  • some proteins in cytoskeleton associated with movement of subcellular structures, e.g. chromosomes using chemical energy in ATP bonds
  • bind adjacent cells together or form part of extracellular matrix
  • sensors - some change shape as conditions in a cell change, e.g temp, ion conc., pH etc.
  • embedded in plasma membrane - import and export molecules and ions in cell
    cell signalling - hormones or receptors
    transcription factors - turn genes on or off
19
Q

who discovered DNA and when

A

Watson and Crick - 1953
- based on X-ray crystallography by Rosalind Franklin

20
Q

simple DNA strcuture

A

two long helical stands coiled around a common axis to form a double helix structure
- bases projected from sugar phsophate backbone
- complementary bases join via weak hydrogen bonds, AT and CG

21
Q

why is the double helix shape so important

A

allows heredity - transfer of genetically determined characteristics from one generation to the next

22
Q

four cyclic organic bases in DNA

A

ATCG

23
Q

what does complementary base pairing allow in DNA molecules

A

allows DNA replication and inheritance, and zipping back together of complementary strands in correct conditions
- other DNA techniques such as electrophoresis, DNA sequencing etc.

24
Q

where is genetic info held in DNA

A

its sequence - linear order of nucleotides along a strand

25
Q

what are genes

A

specific segments of DNA

26
Q

How many protein encoding genes for some organisms

A

bacteria - a few thousand
yeast and other unicellular eukaryotes - ~5000
humans and other metazoans ~13000 - 23000
Plants - many more than animals

27
Q

What are metazoans

A

Eukaryotic multicellular organisms - most animals

28
Q

what are conserved genes

A

genes that have …

29
Q

two processes in protein encoding and production

A

transcription and translation

30
Q

Transcription and translation simple

A

Transcription: protein coding region of gene os copied into single stranded RNA
- the RNA contains the same sequence as the double stranded DNA - uses it as a template
- RNA polymerase catalyses linkage of nucleotides with complementary bases via condensation reaction (produce phosphodiester bonds) using DNA as a template
- RNA is processed into mRNA, which moves out of the nucleus via nuclear pores to the cytoplasm adn to the ribosome
- Ribosome (composed of RNA and proteins) attaches to mRNA and carries out translation
Translation: ribosome assembles and linsk together amino acids in precise order dictated by mRNA sequence - according to the genetic code

31
Q

RNA uses

A
  • transcription and translation in protein biosynthesis
  • catalyse some reactionss - certain RNA molecules catalyse peptide bond formation between amino acids
32
Q

How do genes affect different cell types

A

certain genes are transcribed in different cells.
Some genes may be active/turned on to make proteins, or turned off (via transcription factors).

33
Q

Two main parts of protein-encoding genes

A
  • coding region - specifies amino acid sequence of protein
  • regulatory region - where transcription factors activate or repress transcription of certain genes
  • meaning the regulatory region controls when and in which cells the gene’s encoding protein is made
34
Q

Main function of phospholipids

A

Phospholipid bilayer in plasma membranes

35
Q

Basic structure of plasma membranes - phospholipid bilayer

A

bipartite
- hydrophilic phosphate head - faces outwards
- hydrophobic fatty acid tail - facing inward
- transmembrane and transport proteins
- cholesterol scattered throughout - regulated fluidity of membrane

36
Q

function of some proteins in plasma membrane

A

phospholipid bilayer impermeable to water
- so transport proteins used to move certain molecules and ions in and out of the cell
- used to attach cell to other cells or to surrounding polymers
- some give the cell its shape or allow it to change shape

37
Q

risks of damaged DNA
- what defences are there against this

A

UV and gamma radiation, as well as some chemical may damage DNA
- this can cause mutations
- causes errors in DNA replication

38
Q

risks of damaged DNA
- what defences are there against this

A

UV and gamma radiation, as well as some chemical may damage DNA
- this can cause mutations
- causes errors in DNA replication
- can cause uncontrolled cell growth - tumour formation etc.
- ther are checkpoints in the cell cycle and other mechanisms that can prevent erroneous DNA replication

LF104: Molecules, Cells And Organisms (25 decks)

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