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Year 12 Bio > 1.2 - 2.1 - bio mols 1 and eukaryotic cells > Flashcards

1.2 - 2.1 - bio mols 1 and eukaryotic cells Flashcards

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1
Q

v
How are triglycerides formed

A

When a glycerol molecule reacts with 3 fatty acids to form an ester bond. (Condensation reaction as h20 removed)

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2
Q

Saturated lipids
Unsaturated

A

S - contain single bonds
U - contain carbon carbon double bonds , creating kinks in the chains so its harder for them to pack together tightly as it increases the space between phospholipids

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3
Q

How does the structure of lipids relate to its role in , waterproofing, energy transfer , insulation

A

Water - they are
non polar and hydrophobic so they won’t dissolve in water
Energy -

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4
Q

What is a phospholipid?
How can the structure of a phospholipid control what enters and leave a cell ?

A

A lipid made of one phosphate molecule , glycerol mol and 2 fatty acids
Phosphate heads are hydrophilic and the tails are hydrophobic

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5
Q

Explain the arrangement of phospholipids in a membrane

A

-Bi layer
Phosphate head orientated outside, so they can interact with the aq envir
Fatty acid tails within the bilayer as they turn away from the solution

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6
Q

Amino acids combine in a long chain to produce proteins in

A

Condensation reaction

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7
Q

The primary structure ..
Secondary structure of protein …

A

of a protein is the linear sequence of amino acids joined by peptide bonds
The curling or folding of the poly peptide chain into alpha helixes and beta pleated sheats due to the formation of hydrogen bonds .

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8
Q

How are polypeptides formed (lots of amino acids join )

A

The amino group of an aa reacts with the carboxyl group of another aa in a condensation reaction where a water molecule is lost.

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9
Q

How is a peptide bond formed

A

When 2 amino acids join together

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10
Q

Tertiary structure
Quaternary structure

A

3D folding of the secondary structure , joined by disulfide bonds
3D arrangement of more than one tertiary polypeptide

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11
Q

How do hydrogen bonds form
How do disulfide bonds form?

A

In aa the negative charges on the oxygen of the carboxyl group and positive charges on the hydrogen atoms attract .
Oxidation reaction takes place between the two sulphur containing groups resulting in a covalent bond

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12
Q

How do ionic bonds form?

A

They form between some of the strongly positive and negative amino acid sidechains.

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13
Q

In a phospholipid the head is

A

Polar and hydrophilic , because it has a charge it’s attracted to water
Non - polar hydrophobic

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14
Q

Cholesterol …

A

Is a molecule made in the liver regulates fluidity and permeability of the cell membrane

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15
Q

Lipids containing saturated fatty acids are more likely to be

A

Solid at room temp than those containing unsaturated fatty acids

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16
Q

plasma membranes are composed of proteins arranged randomly amongst the phospholipids. what are they

A

extrinsic proteins - occur on the surface of the bilayer or partially embedded in it

intrinsic - extend thru the whole membrane form one side to another

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17
Q

why should cell surface membranes be flexible ?

A

so the cell can change shape slightly as its water content changes

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18
Q

functions of proteins in the membrane are to:

A
  1. provide structural support
  2. act as carriers transporting water soluble substances across the membrane
  3. form recognition sites by identifying cells
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19
Q

why are cholesterol molecules distributed across the phospholipid bilayer?

A

to help it stay fluid in different environmental conditions
-it also holds the phospholipids together so they dont separate too far letting unwanted substances in

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20
Q

What’s the function of the nuclear membrane/envelope in a nucleus
Nuclear pores
Nucleolus

A

Controls exit of materials in and out nucleus
Hole in the nuclear envelope , allowing mrna molecules to pass thru after transcription
Contains almost pure DNA and protein

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21
Q

In a mitochondria what are the
Mitochondrial dna
Cristae (highly folded inner membrane)
Outer membrane

A

Allows mitochondrial enzymes to be created
Increases SA for enzymes involved with respiration to attach to
Controls passage of substances in and out cell

22
Q

In a mitochondria what’s the function of
Matrix (cytoplasm )
Ribosome
ATpase enzyme

A

Fluid filling mitochondrion
Site of protein synthesis
Enzyme used in respiration

23
Q

70s ribosomes
80s

A

Found in prokaryotic cells
Made up of a smaller 30 sub unit and larger 50s

Eukaryotic cells , 40s small and 60s large

24
Q

What’s the job of a SER

A

Synthesises , stores and transports lipids and steroids

25
Q

Describe the structure of an ER

A

Double membrane highly folded into cisternae forming a channel thru out the cell , folding increase sa for reactions In the cell

26
Q

List properties of fibrous proteins

A

Long parallel polypeptide chains with occasional cross linkages that form into fibres
They are insoluble and tough
Mainly secondary struc

27
Q

Collagen..

A

Is a fibrous protein and provides strength to other structures
The Fibres are strong bc of it being made of 3 polypeptide chains held by hydrogen bonds
- flexible due to kinks in protein chain

28
Q

Globular proteins …

A

Tertiary / quaternary struc
Folds into spherical globular shape
Holds molecules in position in cytoplasm

29
Q

Haemoglobin…

A

-globular protein and water soluble
4 polypeptide chains held tog by disulfide bonds

30
Q

Glycoproteins ?
Lipoproteins ?

A

Protein w carbohydrate prosthetic group
Protein w lipid prosthetic group

31
Q

What’s a monosaccharide, disaccharide and polysaccharide

A

M - single carbohydrate monomer
D- 2 carbohydrate monomers joined together
P - many monosaccharides joined

32
Q

What’s a glycosidic bond ?

A

A covelant bond formed when 2 monosaccharides join in a condensation reaction , a mol of water is removed and a disaccharide formed

33
Q

A glycosidic bond between 2 monosaccharides is split by

A

Hydrolysis where water is added to the bond

34
Q

What is starch amylose?

A

-made up of alpha glucose molecules joined by 1.4 glycosidic bonds , unbranched polymer
- as chain lengthens molecules spiral making it more compact for storage
-helical

35
Q

What is starch amylopectin?

A
  • branched polymer of glucose molecules
  • branching chains = more terminal glucose molecules can be broken off rapidly when needed
    -1.4 AND A FEW 1.6 bonds
    -branched
    Function: releases glucose rapidly when needed
36
Q

What is glycogen? polyosaccharide

A
  • Alpha glucose, 1.4 and many 1.6 glycosidic bonds,
    branched meaning glucose broken down rapidly making it a source of glucose for cellular respiration
37
Q

What is cellulose? Structure and function

A

Beta glucose, 1.4 glycosidic bonds, hydrogen bonds hold molecules together, unbranched
- provides strong cell wall to prevent cell lysis ( H 2 )

38
Q

How does the Golgi apparatus and rer work together?

A
  • Rer packages proteins into vesicles which pinch off
  • vesicles then fuse w Golgi body emptying contents into golgi sacs
  • golgi modifies protein , by adding carbohydrate
  • if modified protein leaves the cell it’s packaged into vesicles and fuses w cell surface membrane for exocytosis
  • golgi produces lysosomes
39
Q

What are lysosomes and how does it work

A

-Spherical vesicles containing digestive enzymes
- they destroy old surplus organelles

  • materials from outside the cell fuse w cell membrane it’s taken into cell ,packaged into membrane bound vesicles . Lysosome fuses with v, releasing its contents digesting it
40
Q

Define apoptosis

A

The breakdown of worn out damaged or diseased cells by lysosomes

41
Q

Describe the structure of plant cell walls

A
  1. Middle Iamella is made of pectin and forms calcium pectate which binds to cellulose on either side
  2. Primary wall - made of microfibrils and matrix built up on either side of iamella, microfibrils in same direction so very flexible
  3. Secondary wall - microfibrils lie at diff angles as cell ages
42
Q

What is plasmodesmata in plant cells

A

Strands of cytoplasm which stretch between cells , water can move from cell to cell via this route (symplast pathway)

43
Q

Vacuoles ..

A

Surrounded by tonoplast membrane , cell sap from vac moves into cell by osmosis making cytoplasm press against cell wall keeping cells turgid .

44
Q

Chloroplasts..

A

Have a double membrane, the inner membrane is highly folded to form thylakoids.
It absorbs light energy for photosynthesis and converts it into chemical energy .

45
Q

Amyloplasts

A

Colourless organelles and are developed from leucoplasts , they store starch

46
Q

In Complex organisms cells are organised into..

A

Tissues - a group of specialised cells carrying out particular function in body
Organs - structure made up of several types of tissues grouped together to carry out a particular function in the body
Organ system - group of organs working together to carry out particular function in the body .

47
Q

Explain how the properties of water molecules result in surface tension

A

-Water molecules are polar
-therefore form hydrogen bonds therefore are cohesive

48
Q

Why is water a polar molecule ?

A

Covelantly bonded , electrons attracted to stronger positive charge of the atom w the largest no of protons , in this case oxygen .
End of molecule has slight - charge , hydrogen end = slightly +

Electrons held closer to oxygen atom than hydrogen , water form’s hydrogen bonds, cohesive

49
Q

Importance of water :
1.high specific heat capacity
2. Maximum density 4 degrees

A
  1. H bonds between molecules means it takes a lot of energy to separate them so temps of lakes etc don’t change much throughout the year , making good habitats
  2. When cooled to 4 degs mols are closest together , ice floats forming an inuslating layer protecting aquatic organisms
50
Q

Importance of water :
3. Incompressibility
4. Polar solvent

A
  1. Water is a liquid so can’t be compressed
  2. Water contains hydrogen bonds . water is a solvent so polar molecules can dissolve in water

Year 12 Bio (5 decks)

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