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A Level Biology - Seneca Topic Flashcards > Topic 2 > Flashcards

Topic 2 Flashcards

1
Q

What happens when an organism inc in size

A
  • Volume increases

- Greater size of organ, lowe SA:V

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2
Q

What are Exchange Surfaces adapted for

A

-efficiency of gas and solute exchange across them

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3
Q

Thin Membrane adaptation for Gas Ex

A

-reduces diffusion distance

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4
Q

Large Surface Area adaptation for Gas Ex

A

-Allows a greater amount of substance to diffuse at the same time

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5
Q

Blood Vessels adaptation for Gas Ex

A
  • In animals, substances are exchanged through blood

- exchange surfaces densely packed to replenish blood supply

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6
Q

Exchange surfaces adaptation for Gas Ex.

A

-maximise the efficiency of gas and solute

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7
Q

Ficks Law

A

-Rate of Diffusion = (SA x Conc diff)/thickness of surface

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8
Q

Diffusion rate in Ficks Law

A

-DR is higher when SA and Diff C are larger, thickness of Surface is smaller

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9
Q

What aids Active Transport?

A

-Carrier Proteins - Facilitates movement

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10
Q

Example of Active Transport?

A
  • Sugar Absorption in the gut
  • allows sugar molecules (respiration) to be absorbed into blood via gut
  • even when sugar conc. in blood higher
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11
Q

Two Main factors of Active Transport?

A
  • SA of cell membranes

- Number of carrier proteins in cell membranes

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12
Q

What is Active Transport?

A
  • Molecules move from a less conc. solution too higher conc. solution against a concentration gradient
  • Energy via respiration
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13
Q

What type of structure is an enzyme determined from

A

-tertiary

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14
Q

What is the Enzyme Active Site?

A
  • Only catalyses one specific reaction

- Complementary to the specific substrate

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15
Q

Environmental factors that determine the specificity of the enzyme?

A
  • 3D tertiary structure

- Polyp. chain determines Active site

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16
Q

How do enzymes catalyse reactions?

A

-Lowering the activation energy

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17
Q

Activation Energy?

A

-Amount of energy needed for the reaction to take place

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18
Q

Lock and Key Hypothesis

A

-Proposes that enzyme and substrate fit together perfectly

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19
Q

Induced fit Theory?

A

-More dynamic interaction

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20
Q

Bronchioles

A

-Millions of small branches throughout lungs

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21
Q

Alveoli

A

-Sacs that fill with air when breath in

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22
Q

Bronchi

A

-Air flows along the lungs

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23
Q

Trachea

A

-Entrance to gas exchange system

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24
Q

3 things Ventilation is controlled by

A
  • Bones that form the ribcage
  • Diaphragm
  • Intercostal Muscles
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25
Q

Capillaries role in gas exchange

A
  • Surrounds Alveolis

- Provide a large surface area

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26
Q

Alveolar Epithelium

A
  • Single Layer
  • Provide very short diffusion distance
  • Maximises gas exchange rate
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27
Q

Concentration Gradient at the Alveoli

A
  • Capillaries provide Co2, ,Oxygen at Alveoli

- Steep concentration gradient

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28
Q

What does the Permeability of the Cell Membrane depend on

A
  • Solvent Concentration
  • pH
  • Temperature
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29
Q

What are Phospholipids made out of

A
  • Glycerol
  • Two Fatty Acids
  • Phosphate
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30
Q

Where is cholesterol in the membrane

A
  • Core of the Membrane

- Maintains shape of animal cells

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31
Q

Solvent Concentration effect on Phospholipid Bilayer and how can it be controlled?

A
  • More easily dissolved = More Permeable membrane

- Can be Controlled if using same Solvent for each trial

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32
Q

pH effect on Phospholipid Bilayer and how can it be controlled?

A
  • pH affects protein structure

- Buffer solutions can control this

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33
Q

Temperature effect on Phospholipid Bilayer and how can it be controlled?

A
  • Higher temp increases fluidity of bilayer

- using a water bath

34
Q

First Step of Cell Membrane Beetroot Practical

A

-Collect Beetroot Sample

35
Q

Second Step of Cell Membrane Beetroot Practical

A

-Place samples in Ethanol for 10 minutes

36
Q

Third Step of Cell Membrane Beetroot Practical

A

-Remove discs from solutions

37
Q

Fourth Step of Cell Membrane Beetroot Practical

A

-Calibrate the Colorimeter

38
Q

Fifth Step of Cell Membrane Beetroot Practical

A

-Measure the absorbance of each solution

39
Q

5 Steps of Cell Membrane Beetroot Practical

A

1) Collect Beetroot Sample
2) Place samples in Ethanol for 10 minutes
3) Remove discs from solutions
4) Calibrate the Colorimeter
5) Measure the absorbance of each solution

40
Q

Plasma Membrane

A

-Structure that defines the border of cells

41
Q

Glycoproteins and Glycolipids function

A

-signalling receptors

42
Q

Osmosis

A

-Diffusion of water across a partially permeable membrane from a low concentration solution to a high concentration solution

43
Q

Partial Permeable Membrane

A

-Allows water through, not larger molecules

44
Q

Primary Structure of Proteins

A

-Dependent on structure of Amino Acids

45
Q

Amino Acid Sequence

A

-Specific sequence to determine Primary Structure

46
Q

Importance of a change in amino acid sequence

A
  • Could lead to change in amino acid being produced

- Could change structure and function

47
Q

Secondary Structure of Proteins

A

-Polypeptide chain folding

48
Q

Hydrogen bonds in Polypeptide chain determining Secondary Structure?

A
  • Amino Acids can form hydrogen bonds between eachother

- These cause chain to fold which determines secondary structure

49
Q

Common Features of Secondary Structure

A

-Alpha Helix and Beta Pleated Sheets

50
Q

Stability in Secondary Structure

A
  • High Number of bonds leads to stability

- Can be affected via environmental factors - pH, Temp

51
Q

Tertiary Structure

A
  • Secondary structure folds even more

- Creates Three Dimensional shape

52
Q

R groups effect on Tertiary Structure

A
  • Side chains on amino acids

- Interactions between R groups lead to 3D structure

53
Q

Quaternary Structure

A

-3D polypeptides come together to form this structure

54
Q

Examples of Quaternary structure

A
  • Haemoglobin

- Insulin

55
Q

Haemoglobin Quaternary structure features

A

-four polypeptides surrounding central Haem group

56
Q

Insulin Quaternary structure features

A

-Combination of Hydrogen bonds and Disulfide bridges

57
Q

What is Exocytosis and Endocytosis responsible for?

A

-Ways in which substances can be actively transported across membranes using ATP

58
Q

Endocytosis?

A
  • Cell engulfs a substance from its surroundings

- Fluid cell membrane folds around substance

59
Q

Exocytosis?

A
  • Membrane-bound vesicles fuse with plasma membranes before releasing into surroundings
  • used when cells produce a substance which needs to be exported
60
Q

Transcription?

A

mRNA produced in the nucleus

61
Q

Transcription steps?

A

1) Binding of RNA Polymerase
2) Separation of DNA strands
3) Binding to template strands
4) Joining the Nucleotides
5) STOP codon
6) Removal of mRNA
7) mRNA leaves Nucleus

62
Q

Transcription - (1)Binding of RNA Polymerase

A
  • This enzyme allows transcription to take place

- Binds to Locus of gene

63
Q

Transcription - (2)Separation of DNA strands

A
  • When RNA Poly. binds to DNA

- Triggers Hydrogen bonds so DNA unwinds (exposes bases)

64
Q

Transcription - (3)Binding to Template strands

A
  • RNA Poly. binds free floating RNA nucleotides to template strands
  • This forms mRNA - complementary to the gene
65
Q

Transcription - (4)Joining the Nucleotides

A

-Phosphodiester bonds formed in between nucleotides

66
Q

Transcription - (5)STOP Codon

A

-RNA Poly. reaches stop codon ‘UAG’

67
Q

Transcription -(6)Removal of mRNA

A

-mRNA strand separated from template by RNA Poly.

68
Q

Transcription -(7)mRNA leaves nucleus

A

-mRNA leaves nucleus and enters cytoplasm

69
Q

Translation steps?

A

1) Attachment to Ribosome
2) Binding of tRNA
3) Bringing in Amino Acids
4) Binding of Second tRNA
5) Movement of the Ribosome
6) STOP Codon
7) Completion of Polypeptide

70
Q

Translation -(1)Attachment to Ribosome

A

-mRNA binds to Ribosome (sight of Protein Synthesis)

71
Q

Translation -(2)Binding of tRNA

A
  • One Molecule of tRNA binds to first codon in ribosome

- tRNA has anticodon complementary to specific codon

72
Q

Translation -(3)Bringing in Amino Acids

A

-Each tRNA molecule carries a specific amino acid to the ribosome

73
Q

Translation -(4)Binding of Second tRNA

A
  • tRNA binds to second codon in ribosome
  • tRNA binds to mRNA, corresponding amino acid is brought to ribosome
  • Peptide bond formed between amino acids
74
Q

Translation -(5)Movement of the Ribosome

A
  • When amino acid is formed

- Ribosome moves along mRNA strand so new codon enters ribosome

75
Q

Translation -(6)STOP Codon

A

-Ribosome reaches UAG then stops

76
Q

Translation -(7)Completion of Polypeptide

A

-Polypeptide chain formed

77
Q

How does DNA Replication Occur

A
  • each of two DNA strands used as template

- New strands copied

78
Q

What is DNA made up of

A

-Two Polynucleotide strands that form a double helix

79
Q

Why is DNA known to be Semi-conservative

A
  • After Replication DNA is made up of one polynucleotide strand
  • One original strand is conserved
80
Q

3 steps of DNA Replication

A

1) DNA helicase binds to DNA and breaks hydrogen bonds between strands (strands separate)
2) Free-floating Nucleotides form hydrogen bonds with complementary bases
3) DNA polymerase forms Phosphodiester bonds between nucleotides

81
Q

What is DNA Polymerase responsible for?

A
  • Catalyses condensation reaction between nucleotides in DNA strand
  • forms phosphodiester bonds between adjacent nucleotides
82
Q

Watson and Crick’s discovery of DNA replication

A
  • Specific base pairing involved in copying sequences of genetic information
  • thought each strand = template which complementary strand copied
  • Did not know how replication took place

A Level Biology - Seneca Topic Flashcards (8 decks)

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