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Biology - Unit 1 > Life at Cellular Level > Flashcards

Flashcards in Life at Cellular Level Deck (79):
1

Why are cells small?

Small cell keeps a large surface area to volume ratio - needed for easy absorption of substances

2

Do prokaryotes have mitochondria?

No

3

What is the difference between pluripotent cells and multipotent cells?

Multipotent - can differentiate into many cell types Totipotent - can differentiate into every type of cell in the body

4

What are the key differences between necrosis and apoptosis?

Necrosis - Days, groups of cells, damage to neighbouring cells, inflammation Apoptosis - Hours, individual cells are induced to die, no damage to neighbouring cells, no inflammation

5

Describe the shape of mitochondrial DNA

Circular

6

What does the endoplasmic reticulum do?

Site of protein and glycolipid synthesis

7

Which proteins does the golgi apparatus add sugars to?

Membrane proteins Lysosomal proteins Secretory proteins

8

What is the word used to describe membrane lipids?

Amphipathic

9

What function do telomeres have?

They stabilise the ends of the chromosomes

10

What function do centromeres have?

They ensure distribution of chromosomes to daughter cells when the cell divides

11

What is splicing?

Removing introns during translation

12

What is the ribosome composed of?

Ribosomal RNA

13

What is responsible for autophagy?

The lysosome

14

What is the function of the cytoskeleton?

Holds organelles in place and moves them Supports and maintains cell shape

15

What three structures comprise the cytoskeleton?

Microfilaments Intermediate filaments Microtubules

16

What is the structure of microfilaments?

Made up of actin protein strands - thin and contractile

17

What are microfilaments responsible for?

Provide structure Cell cell anchoring

18

What is the structure of intermediate filaments?

Consists of fibrous proteins, organised in tough rope-like assemblages

19

What is the function of intermediate filaments?

Stabilise cell structure, prevents collisions within the cell

20

What is the structure of microtubules?

Thick Long, hollow cylinders made from tubulin (a dimer composed of alpha and beta tubulin)

21

What is the function of microtubules?

Transport materials in cytoplasm

22

What is the peroxisome responsible for?

Oxidation of fatty acids

23

What type of atoms form the strongest bonds?

Light atoms

24

What are the two isomers of the c-c double bond?

Cis (meaning same) Trans (meaning opposite)

25

What are the names given to the two forms of carbon?

Laevo (left handed) Dextro (right handed)

26

What type of amino acids are proteins made from?

Left handed (laevo)

27

What is defined as comformation?

The precise arrangement of atoms in a molecule

28

What is the intermediate product between glucose and pyruvic acid, and what products does its formation produce?

Phosphoglyceraldehyde Makes 2 ATP each Makes 1 NADH each

29

Is condensation a synthesis or degradation reaction, what does it always produce?

It is a synthesis reaction that produces water

30

What type of reaction occurs between the pentose sugar of one nucleotide and the phosphate of an adjacent nucleotide?

Dehydration reduction

31

What is the difference between a nucleoside and a nucleotide?

Nucleoside does not contain a phosphate group

32

What does the 5' end of RNA contain?

Contains the phosphate

33

What enzyme is used to insert viral DNA into the host genome?

Insertase

34

What is the effect of zidovudine?

It is a reverse transcriptase inhibitor and prevents the virus producing DNA from RNA

35

What is the structure of triaclyglyceride?

A glycerol backbone connected to three fatty acids

36

What is the structure of a lipid?

Carboxyl head and a hydrocarbon chain

37

What is the structure of a phospholipid?

Same structure as triacylglycerol except one of the fatty acids has been replaced with a phosphate group (forming the hydrophilic head)

38

Are triacylglycerides polar?

No

39

What is the definition of amphipathic?

A molecule having both hydrophilic and hydrophobic parts.

40

What is the first law of thermodynamics?

Energy can neither b converted nor destroyed

41

What is the second law of thermodynamics?

All energy transformations ultimately lead to more disorder, an increase in entropy

42

What is enthalpy defined as?

The total energy within a system

43

What is entropy defined as?

The disorder within a system

44

What is the equation to calculate gibbs free energy?

A image thumb
45

What is free energy measured in?

Kcal/mol

46

What does a delta G less than 0 indicate?

The reaction is spontaneous and energy releasing

 

 

47

What does delta G greater than 0 indicate?

That the reaction is spontaeous backwards (endergonic)

48

What does a delta G equal to 0 mean?

The reaction is at equilibrium

49

What type of delta G do biological reactions require?

Positive delta G, since they require more order rahter than less

50

What is meant by energy coupling?

An energetically unfavourable reaction is driven by an energetically favourable reaction.

51

What are the features of catabolism reactions?

Heat loss

Complex oranic molecules are broken down into simpler ones

Releases energy that drives chemical reactions

52

What are the features of anabolic reactions

Simpler substances are combined to form more complex molecules

Require energy

53

How do exergonic reactions save free energy?

By forming ATP

54

What is the definition of an apoenzyme?

Require non-protein co-factors

55

What makes up a holoenzyme?

Cofactor + apoenzyme

56

What is the function of water?

Bathes our cells

Dissolves and transports compounds

Allows compounds to move between and within cells

Participates in chemical reactions

Dissipates heat

57

Which atom are electrons held closer to in an OH bond?

They are held closer to the O atom because the O is more electronegative

58

Describe the H bonds in water?

They are continually forming and breaking whilst H2O molecules move

59

Does gaseous H2 contain H bonds?

NO

60

Where does a hydrogen bond take place?

Between any any eectonegative atom and an H atom that is electropositive

61

When are H bonds strongest?

When the three atoms involved lie in a straight line

62

What is the change in H bonding when a hydrophilic molecule like alcohol, aldehyde or ketone is dissolved in water?

H bonds within water and the solute are replaced with more energetically favourable solute-water H bonding

63

Why is O2 and CO2 poorly soluble in water?

No polarity

64

Describe the structure of dissolved sodium chloride

Water forms screens around each ion

65

What effect does does the interaction between a substrate and an enzyme have on the order of water?

Enzyme substrate reaction displaces dsordered water

66

What is meant by the hydrophobic effect?

They arrange themselves in water to minimise the disruption of hydrogen bonding in the surrounding water molecules

This is energetically favourable

67

Describe the structural arrangement of water around alyl chains?

H2O molecules form cages around hydrophobic alkyl chains

68

How do phospholipids minimise disruption of H bonding in solution?

They form bilayers or mxed micells

69

What kind of structure will proteins adopt when they are in aqeous solution?

They fold up so that the hydrophilic parts of the chain are on the outside and the hydrophobic parts are on the inside, allowing them to be water soluble.

70

What calculation is used to calculate the dissociation of water?

A image thumb
71

What does Kw (ionic product of water) always equal in the dossociation of water

1x10-14

72

How do you calculate pH from the concentration of H+?

pH = -Log [H+]

73

How do you describe the movement of protons in both acids and bases?

Acids are proton donors and bases are protein acceptors

74

What equation is given to the equilibrium constant of an acid?

A image thumb
75

What does the euilibrium constant measure?

It measures the tendancy for any acid to lose a proton and form its conjugate base

76

What is pKA?

It is the -log of the acid dissociation constant

77

What is significant about the midpoint of the titration of a weak acid and a base?

Exactly half of tha base is added and half the weak acid is remaining

 

pH = pKa

78

What is the henderson hasslebalch equation?

A image thumb
79

What are natural buffers in the body?

Phosphate in the cells

Bicarbonate in the blood