Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOLOGY > lipids, water + inorganic ions > Flashcards

lipids, water + inorganic ions Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

define what is meant by lipids .

A
  • lipids contain carbon, hydrogen + oxygen atoms - O2 atoms in lipids molecules then in carbohydrates .
  • fats - solid at room temp & oils are liquid .
  • fatty acids contain -COOH group + long hydrocarbon attached = (‘R’ —> ‘RCOOH’.)
  • non-polar = don’t have uneven distribution of charge.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how do triglycerides form?

A
  • condensation reaction between 1 molecule of glycerol (C3H8O3) + 3 fatty acids (3 hydroxyl (OH) which joined through ester bonds.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

contrast saturated and unsaturated fatty acids .

A

SATURATED .
- contain single bonds,
- straight chain molecules have many contact points,
- higher melting points —> solid at room temp ,
- found in animal fats

UNSATURATED
- contains C=C double bonds.
- “kinked” molecules have fewer contact points
- lower melting points - liquid at room temperature
- found in plant oils ,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

explain the features of triglycerides .

A
  • used as energy stores - energy released when the ester bonds are hydrolysed/ oxidised in respiration.
  • triglycerides clump together into lipid droplets —> hydrophobic tails face inwards + hydrophilic heads face outwards.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

relate the structure of triglycerides to their functions .

A
  • high energy: mass ratio = high calorific value from oxidation (energy storage)
  • insoluble hydrocarbon chain = no effect on water potential of cells + used for waterproofing.
  • slow conductor of heat - thermal insulation (adipose tissue: in animals) and thick layers of it “blubber”.
  • less dense than water / buoyancy of aquatic animals .
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe the structure + function of phospholipids .

A
  • glycerol backbone attached to 2 hydrophobic fatty acid tails (face inwards) + 1 hydrophilic polar phosphate heads . ( face outwards)
  • centre of bilyser is hydrophobic - water soluble substances can’t easily pass thru- barrier membrane to those substances .
  • tails can splay outwards = waterproofing .
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

explain why phospholipids do not dissolve in water .

A
  • tail is hydrophobic but head has “negative” charge - “hydrophillic”
  • when placed in water - arrange themselves on the h2o surface with there down and tails up - form spheres in water - “micelles”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

compare phospholipids and triglycerides .

A
  • both have glycerol backbone.
  • both may be attached to a mixture of saturated, monosaturated and polyunsaturated fatty acids .
  • both contain elements ; C, H, O
  • both formed by condensation reactions .
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

contrast phospholipids and triglycerides.

A

PHOSPHOLIPIDS .
- 2 fatty acids + 1 phosphate group attached
- hydrophilic head and hydrophobic tail
- used primarily in membrane formation .

TRIGLYCERIDES.
- 3 fatty acids attached
- entire molecule is hydrophobic
- used primarily as a storage molecule (oxidation releases energy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

are phospholipids + triglycerides polymers ?

A
  • No, they aren’t made from a small repeating unit.
  • they are macromolecules .
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

why is water a polar molecule?

A
  • O is more electronegative than H, so attracts the electron density in the covalent bond more strongly.
  • forms O ẟ- (slightly negative charge) + H ẟ+ (slight positive charge.)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe the process of polarisation regarding water.

A
  • in water - electrons are shared unequally within the bonds that hold a water molecule together
  • oxygen pulls electrons closer towards it and gives oxygen a slight negative charge + hydrogen a slight positive charge .
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

define the term hydrogen bond .

A
  • weak chemical bonds involving hydrogen atoms . - strong intermolecular force.
  • hydrogen bond forms between slightly negative oxygen atom of one water molecule and slightly positive hydrogen atom on another molecule .
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

define the meaning of dipole .

A
  • describing a molecule that has a small positive charge in some areas and a small negative charge in others .
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

state 4 biologically important properties of water.

A

due to polarity + intermolecular H-bonds:

  • metabolite / solvent for chemical reactions in the body
  • high specific heat capacity.
  • high latent heat of vaporisation
    /cohesion between molecules .
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe how specific high capacity may help organisms .

A
  • large amount of energy needed to raise : increase temp of water .
  • all those golden bonds within water good at absorbing energy - add loads to heat h2o
  • “buffers” heat changes = prevents large fluctuations in water temp - keeps temp of aquatic environments stable - organisms not endure extremes of temp.
17
Q

describe how high latent heat of vaporisation may help organisms .

A
  • energy that’s lost from liquid water as it evaporates / lots of energy used to covert water from liquid to gas .
  • provides cooler effect - we feel cooler when we sweat as evaporation of water from our skin’s surface takes a lot of heat energy with it .
18
Q

describe how water is an excellent solvent .

A
  • allows transport substances // so metabolic reactions can occur .
  • because of its polarity and ability to form hydrogen bonds - ions and polar molecules can easily dissolve in it “universal solvent”
    (e.g- hydrophilic molecules dissolve in blood)
19
Q

describe how water is a metabolite .

A
  • acts as a solvent , providing the medium in which most biochemical reactions occurs
  • metabolic in condensation, hydrolysis, photosynthesis, respiration - when water reacts with a chemical to break it into smaller molecules the reaction is described as hydrolysis .
20
Q

explain the difference between cohesion and adhesion.

A
  • adhesion = the force that attracts water molecules to the walls of xylem vessels in a plant
  • cohesion = the way in which molecules “stick” together.
21
Q

describe the cohesion surface tension of water .

A
  • due to hydrogen bonds - formed between partially negative oxygen of one molecule + partially positive hydrogen of another molecule
  • attractions between water molecules allows water to be transported up xylem columns .
  • strong cohesion = surface tension at water - air boundary tension is high
22
Q

describe what is meant by specific heat capacity of a material .

A
  • the energy required to raise 1kg of the material by 1 degree celsius .
23
Q

describe what is meant by the term latent heat is vaporisation .

A
  • the energy that’s lost from liquid water as it evaporates .
24
Q

define the term specific latent heat and the two boundaries that each material contains .

A
  • the amount of energy required to change the state of 1kg of a material without changing its temperature .

—> specific latent heat of fusion : amount of energy needed to melt/ freeze material at melting point

—> specific latent heat of vaporisation : amount of energy needed to boil/condense material at boiling point .

25
Q

what’s the difference between a solute and a solvent ?

A
  • solute = substance that is being dissolved .
  • solvent = substance in which the solute dissolves in.
26
Q

why are hydrogen bonds weaker than strong covalent bonds ?

A
  • constantly breaking + reforming but when large no. present they form strong structure
  • covalent bonds - stronger bonds as loads of energy needed to split hydrogen and oxygen atoms apart .
27
Q

explain the role of hydrogen ions in the body .

A
  • important for respiration + photosynthesis reactions and influences pH if a cell by increasing acidity
  • H+ ions interact with H-bonds + ionic bonds in tertiary structure of proteins cause to denature .
28
Q

explain role of iron ions in body .

A

Fe2+ bonds to porphyrin ring to form haem group in haemoglobin .
haem group binding site to transport 1 molecule of O2 around body in bloodstream .

29
Q

explain the role of sodium ions in the body .

A
  • involved in co-transport for absorption of glucose + amino acids in lumen in gut
  • involved in propagation of action potentials in neutrons
30
Q

explain the role of phosphate ions in the body .

A
  • synthesise biological molecules like nucleic acids/ phospholipids .
  • DNA , ATP
31
Q

describe the role of calcium ions in the body .

A
  • needed for transmission of action potentials , the formation of bone, release of insulin from pancreas and as enzyme cofactor
32
Q

describe role of potassium ions in the body .

A
  • generation of action potentials, muscle contraction , maintaining blood pressure and for activating photosynthesising enzymes in plants .
33
Q

describe the role of ammonium ions .

A
  • important for nitrogen cycle - absorbed by plants and incorporated into amino acids for protein synthesis.
34
Q

describe role of hydrogen carbonate ions in the body

A
  • maintains constant pH in the blood by acting as a buffer .
35
Q

describe role of chloride ions in the body .

A
  • maintains constant pH in blood through process of ‘chloride shift’ + acts as cofactor for enzyme amylase .
36
Q

describe role of hydroxide ion in the body

A
  • changes the pH of the cell by making the area more alkaline .
37
Q

Explain why triglycerides and phospholipids are soluble in ethanol.

A
  • alcohols such as ethanol are non polar . although ethanol has small polar region, the bulk of it is made up of non polar region.
  • non-polar substances able to mix together, so triglycerides and phospholipids able to dissolve in alcohols such as ethanol

BIOLOGY (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions