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Biology > Topic 2- Genes and Health > Flashcards

Topic 2- Genes and Health Flashcards

1
Q

what are the properties of gas exchange surfaces in living organsisms

A
  • large surface area: volume ratio
  • thin
  • steep concentration gradient
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2
Q

fick’s law of diffusion

A

(area of diffusionxdifference in conc)/thickness of exchange surface

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3
Q

how is the structure of the mammalian lung adapted for efficient gas exchange

A
  • alveoli
  • large sfa:vol ratio
  • moist (gases can diffuse)
  • steep concentration gradient (capillaries)
  • one cell thick
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4
Q

hydrophilic definition

A

water loving

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5
Q

hydrophobic definition

A

water hating

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6
Q

polar definition

A

electrons not equally distributed

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7
Q

partially permeable definition

A

only small, non polar molecules can pass through

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8
Q

what are phospholipids made up of

A

phosphate group head (hydrophilic+polar)
phosphoester bond
glycerol
ester bond
fatty acid (hydrophobic+non-polar)

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9
Q

explain how a phospholipid bilyer is formed

A
  1. the hydrophobic non-polar tails arrange themselves so that they are never in contact with an aqueous environment
  2. the hydrophilic polar heads will always face the aqueous environment
  3. They form a double layer
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10
Q

what are integral proteins

A

go all the way through the 2 layers: channel/carrier proteins

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11
Q

what are peripheral proteins (glycoproteins + glycolipids)

A

found on only one layer, often act as enzymes or receptors

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12
Q

what are glycoproteins

A

carbohydrate molecule on the peripheral protein
- involved in cell-to-cell recognition and receptors

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13
Q

what are glycolipids

A

carbohydrate molecule attached to the head of a phospholipid

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14
Q

what is cholesterol

A

Sits between the tails of the phospholipids and maintains fluidity of the membrane by affecting the movement of the phospholipids

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15
Q

Simple diffusion

A

small, non-polar molecules are able to diffuse directly between the phospholipids

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16
Q

Facilitated diffusion

A

large, polar molecules can only cross the phospholipid layer via carrier/channel proteins

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17
Q

channel proteins

A

pores that extend through the membrane
- allows charged substances to diffuse through membrane

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18
Q

carrier protein

A

changes shape to transport molecules from 1 side to other
- causes binding site of the carrier protein to be open on 1 side of the membrane first, and then open on the other side when carrier protein switches shape

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19
Q

active transport

A

movement of molecules and ions through a cell membrane from a region of low conc to one of high conc that requires ATP, carrier proteins (ATP allows protein to change shape)

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20
Q

endocytosis

A
  • cell surrounds a substance with a section of the cell surface membrane
  • membrane engulfs the substance and pinches off to form temporary vacuole
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21
Q

exocytosis

A
  • Vesicles containing the substance pinch off from sacs of the Golgi apparatus
  • vesicles are moved toward the cell surface and fuse with the cell surface membrane to be released outside the cell
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22
Q

osmosis

A

net movement of water molecules from a region of lower solute concentration to one of a higher solute concentration through a partially permeable membrane

23
Q

structure of mononucleotides

A

pentose sugar, nitrogenous base, phosphate group

24
Q

differences between DNA and RNA

A

DNA: Thymine, Deoxyribose, In Nucleus, Double-stranded

RNA: Uracil, Ribose, In ribosome, Single-stranded

25
phosphodiester bond
- formed between phosphate group and pentose sugar - via condensation reaction
26
how are the 2 antiparallel DNA strands held together
hydrogen bonds between nitrogenous bases
27
Gene
A sequence of nucleotide bases that code for the production of a specific sequence of amino acids, to make a protein
28
Process of transcription
1. In the nucleus, gyrase causes DNA to unwind 2. Helicase causes the DNA to unzip, Hydrogen bonds break 3. Exposing the gene to be transcribed 4. complimentary copy of the code from the gene is made by building mRNA - catalysed by DNA polymerase 5. free RNA nucleotides pair up via Hydrogen bonds, with their complementary bases on the exposed strand of unzipped DNA 6. sugar-phosphate groups of these RNA nucleotides are then bonded together in a reaction to form the sugar phosphate backbone of mRNA 7. when mRNA is completed, hydrogen bonds break between DNA and mRNA 8. mRNA leaves nucleus via pore in nuclear envelope
29
anti-sense/template strand
produces the mRNA molecule - RNA polymerase moves along template strand in 3'-5' direction - mRNA grows in 5'-3' direction
30
sense/coding strand
provides the code to make a protein
31
translation
1. in the cytoplasm, mRNA attaches to ribosome 2. in cytoplasm there are free molecules of tRNA: - a single stranded RNA that folds into a clover like structure - have a triplet of unpaired bases at one end (anticodon) and a region at the other end where a specific amino acid can bind to 3. tRNA molecules bind with their specific amino acids and bring them to the mRNA molecule on the ribosome 4. anticodon on each tRNA molecule pairs with a codon on the mRNA 5. Two tRNA molecules fit onto the ribosome at any one time 6. Peptide bond formed via condensation reaction between 2 amino acids 7. Process repeats until stop codon on mRNA is reacted 8. Amino acid chain then forms the final polypeptide
32
triplet code
- determines the sequence of dna nucleotide bases found within a gene - each triplet of bases in a gene codes for 1 amino acid -
33
features of the genetic code
Overlapping - each base is only read once - adjacent codons don't overlap - no single base can take part in the formation of more than 1 codon Degenerate - 4 bases, 4 difference codons possible - only 20 commonly occurring amino acids - (Multiple codons code for same amino acid) - can limit the effects of mutations Universal - every organism uses same code - reason why genetic engineering is possible
34
general structure of amino acid
Amine group - ( H-C) - R group - Carboxycillic group
35
Peptide bond
- forms between amino acids - OH is lost from carboxyl group - H atom is lost from amine group - condensation reaction - dipeptides are formed by the condensation of 2 amino acids - polypeptides are formed by the condensation of many amino acids
36
hydrolysis
breaks down the peptide bonds by adding water
37
primary structure
the sequence of amino acids bonded by peptide bonds - DNA determines the primary structure of a protein by instructing the cell to add certain amino acids in specific quantities in a certain sequence. This affects the shape and therefore the function of the protein
38
secondary structure
a regular, repeating 3D structure that coils into: 1. alpha helices - occurs when the hydrogen bonds form between every 4th peptide bond 2. beta pleated sheets - forms when the protein folds so that 2 parts of the polypeptide chain are parallel so H bonds can form between peptide bonds
39
what type of proteins have a secondary structure
fibrous e.g. collagen, keratin
40
tertiary structure
Further conformational change of the secondary structure leads to additional bonds forming between R groups - H bonding (between R groups) - Disulphide bonding (between cysteine amino acids) - Ionic bonding (between charged R groups) - Weak hydrophobic interactions - between non polar, R groups
41
what type of proteins have a tertiary structure
3D globular
42
Quarternary structure
occurs in proteins with more than one polypeptide chain working together as a functional macromolecule - same bonds as tertiary
43
structure of globular proteins
polypeptide chain is folded into a compact and spherical shape - their non-polar hydrophobic R groups orientate themselves on the inside of the protein away from aq environment - polar hydrophilic R groups orientate themselves on outside
44
function of globular proteins
soluble - hydrophillic side chains can form weak H bonds with water allowing them to dissolve used in metabolic reactions
45
haemoglobin
- protein found in RBCs, responsible for transporting oxygen to tissues - conjugated protein - consists of 4 polypeptide units: 2 alpha helices + 2 beta chains
46
conjugated protein
has a haem prosthetic group (non-protein)
47
structure of fibrous proteins
- long strands of polypeptide chains that have cross linked due to H bonds - little to no tertiary structure
48
function of fibrous proteins
- insoluble, hydrophobic R groups - suitable for structural roles
49
collagen
- formed from 3 polypeptides chains, closely held together by H bonds to form a triple helix - high tensile strength: each collagen molecule is held together by covalent bonds (crosslinks) resulting in collagen fibril
50
Enzymes
- biological catalysts - globular proteins with complex tertiary structures
51
intracellular enzymes
produced and used in the cell e.g. catalase
52
extracellular enzymes
secreted and catalyse reactions out of cells e.g. digestive / hormones
53
catalase function
- hydrogen peroxide is produced as a by-product of many metabolic reactions: it's harmful to cells - catalase converts it to water and oxygen, preventing damage to cells
54

Biology (2 decks)

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