B1.1 Carbohydrates and Lipids Flashcards
1
Q
What are carbohydrates composed of?
A
Carbon, Hydrogen, and Oxygen
Carbohydrates are organic compounds that consist of these three elements.
2
Q
What are the recurring monomers that make up carbohydrates?
A
Monosaccharides
These are the simplest form of carbohydrates.
3
Q
What structural feature do monosaccharides typically form?
A
Ring structures
This occurs due to a chemical reaction between functional groups.
4
Q
What two functional groups react to form a cyclic structure in monosaccharides?
A
Hydroxyl group (-OH) and carbonyl group (=O)
Their reaction connects the structure via an oxygen atom.
5
Q
What is a pentose sugar?
A
A monosaccharide with 5 carbons
Examples include ribose and deoxyribose.
6
Q
What is a hexose sugar?
A
A monosaccharide with 6 carbons
Examples include glucose and fructose.
7
Q
What is the primary role of most monosaccharides?
A
To function as a source of energy for the cell
They are crucial in cellular metabolism.
8
Q
What process do monosaccharides undergo to produce ATP?
A
Oxidation via cellular respiration
This process breaks down monosaccharides to generate energy.
9
Q
What is the most common monosaccharide used as an energy source?
A
Glucose
It is favored due to its chemical properties.
10
Q
Why is glucose considered hydrophilic?
A
It is a polar molecule due to –OH groups
This allows glucose to dissolve in water.
11
Q
What makes glucose a stable molecule?
A
Cyclic structures are energetically favorable
This stability is important for its function in biological systems.
12
Q
How does glucose facilitate transport in the body?
A
It is soluble and stable
This allows for easier movement in aqueous solutions like blood.
13
Q
What type of bonds in glucose contain high energy electrons?
A
C–C and C–H bonds
These electrons can be released through oxidation.
14
Q
What is the ATP yield from glucose oxidation?
A
Large yield of ATP
This is achieved via aerobic cell respiration.
15
Q
What are polysaccharides?
A
Carbohydrate polymers comprised of many monosaccharide monomers
16
Q
Name the three key polysaccharides produced from glucose.
A
Cellulose, starch, glycogen
17
Q
What determines the type of polymer formed from glucose?
A
The isomer of glucose involved and the bonding arrangement between the subunits
18
Q
What subunits compose cellulose?
A
ß-glucose subunits
19
Q
What type of linkages are present in cellulose?
A
Glycosidic linkages between the 1’ – 4’ carbon atoms
20
Q
What subunits compose starch?
A
⍺-glucose subunits
21
Q
Describe the structure of amylose.
A
Solely comprised of 1’ – 4’ linkages organised into a helical structural arrangement
22
Q
What distinguishes amylopectin from amylose?
A
Amylopectin is a branched molecule with both 1’ – 4’ linkages and additional 1’ – 6’ linkages
23
Q
How does glycogen compare to amylopectin?
A
Similar in structure but more highly branched with more frequent 1’ – 6’ linkages
24
Q
What are the polymers of ⍺-glucose used in energy storage?
A
Glycogen is used in animals and starch is used in plants.
25
What reactions can glucose monomers undergo to build or mobilize energy stores?
Condensation or hydrolysis reactions.
26
How are the ⍺-glucose monomers connected in glycogen and starch?
Via 1’ – 4’ glycosidic linkages.
27
What are the two forms of starch?
Linear strands (amylose) and branched (amylopectin).
28
What causes starch to exist in linear or branched forms?
The presence of additional 1’ – 6’ linkages.
29
How does the structure of glycogen differ from amylopectin?
Glycogen is more highly branched and possesses more frequent 1’ – 6’ linkages.
30
What effect does branching have on the structure of polysaccharides like glycogen and starch?
It causes them to adopt a more compact structure.
31
Why are glycogen and starch insoluble in water?
Their large molecular size renders them insoluble.
32
What is the implication of glycogen and starch being insoluble in water?
They are efficient storage molecules but not suitable for transport within aqueous solutions.
33
How can carbohydrates like glycogen and starch be utilized for transport?
They can be readily digested to release monomers for transport to other tissues.
34
Fill in the blank: Glycogen and starch are polysaccharides formed from _______.
⍺-glucose monomers.
35
True or False: Glycogen has less frequent 1’ – 6’ linkages compared to amylopectin.
False.
36
What are lipids primarily composed of?
Hydrocarbon chains (fatty acids) or rings (steroids)
## Footnote
Hydrocarbons are nonpolar molecules.
37
What property makes lipids hydrophobic?
Lipids are composed of nonpolar hydrocarbons that do not dissolve in polar substances like water
## Footnote
This nonpolarity is the reason for their hydrophobic nature.
38
List three benefits of lipids.
* Prevent water loss from leaves
* Coat feathers of bird wings for waterproofing
* Provide a structural framework for cells by forming spontaneous membranes in aqueous solutions
## Footnote
Lipids play crucial roles in various biological functions.
39
How do lipids assist in the absorption of certain micronutrients?
They help the body absorb fat-soluble micronutrients like Vitamins A and D when in food
## Footnote
This is essential for various physiological functions.
40
What is a disadvantage of lipids regarding transportation in the body?
Difficult to transport around the body
## Footnote
This challenge arises due to their hydrophobic nature.
41
How do lipids overcome their transportation difficulty in the body?
By packaging digested fats in a protein coat to become water soluble lipoproteins
## Footnote
This allows for easier transport in the bloodstream.
42
What role do carrier proteins play in the transport of steroid hormones?
They bind to steroid hormones to facilitate their movement through the bloodstream
## Footnote
This is crucial for hormonal signaling.
43
What are simple lipids?
Esters of fatty acids and alcohol (e.g. glycerol)
## Footnote
Simple lipids are the basic form of lipids, primarily consisting of fatty acids and alcohol.
44
What are waxes composed of?
A fatty acid chain linked to a long chain alcohol group
## Footnote
Waxes are primarily used to create waterproof surfaces.
45
What are triglycerides used for?
Energy storage and insulation
## Footnote
Triglycerides consist of three fatty acid chains linked to a glycerol molecule.
46
What do compound lipids include?
Esters of fatty acids and alcohol linked to an additional group
## Footnote
Compound lipids have a more complex structure compared to simple lipids.
47
What are phospholipids made of?
A glycerol molecule linked to two fatty acid chains and one phosphate group
## Footnote
They are a principal component of cell membranes.
48
What is the function of glycolipids?
Facilitate cell-cell interactions
## Footnote
Glycolipids consist of a carbohydrate linked to an ester of fatty acids and alcohol.
49
What are derived lipids?
Substances produced from the hydrolysis of simple or compound lipids
## Footnote
Derived lipids include signalling molecules such as steroids and prostaglandins, as well as cholesterol.
50
Fill in the blank: Waxes are used to create _______.
Waterproof surfaces
## Footnote
Waxes provide a protective barrier against water.
51
True or False: Triglycerides are composed of two fatty acid chains.
False
## Footnote
Triglycerides consist of three fatty acid chains linked to a glycerol molecule.
52
What signaling molecules are included in derived lipids?
Steroids and prostaglandins
## Footnote
Derived lipids are important for various biological signaling processes.
53
What are fatty acids?
Fatty acids are long hydrocarbon chains found in most types of lipids (excluding steroids)
## Footnote
Fatty acids are essential components of lipids, playing key roles in cellular structure and energy storage.
54
What is the typical carbon range in fatty acid hydrocarbon chains?
Most fatty acids typically contain between 4 – 24 carbons
## Footnote
The length of the carbon chain can affect the physical properties and functions of the fatty acids.
55
How can fatty acids be classified?
Fatty acids can be classified according to the presence or absence of double bonds between the carbon atoms in the hydrocarbon chain
## Footnote
This classification is crucial for understanding the chemical properties and biological functions of fatty acids.
56
What characterizes saturated fatty acids?
Saturated fatty acids possess straight hydrocarbon chains with no double bonds
## Footnote
They have the maximum possible number of hydrogen atoms.
57
What are the two types of unsaturated fatty acids?
Unsaturated fatty acids can be either mono-unsaturated (1 double bond) or poly-unsaturated (>1 double bond)
## Footnote
These types of fatty acids have different health implications and physical properties.
58
What are the structural configurations of unsaturated fatty acids?
Unsaturated fatty acids may occur in cis and trans isomers
## Footnote
The configuration affects the shape and function of the fatty acids.
59
What is the difference between cis and trans isomers in unsaturated fatty acids?
Cis: Hydrogen atoms attached to the carbon double bond are on the same side, causing the hydrocarbon chain to kink; Trans: Hydrogen atoms are on different sides, meaning the hydrocarbon chain remains straight
## Footnote
The cis configuration is more common in nature and has different biological effects compared to trans.
60
In living organisms, what configuration do unsaturated fatty acids typically have?
In living organisms, unsaturated fatty acids are nearly always in the cis configuration
## Footnote
Only ruminant animals (cows and sheep) produce trans fatty acids.
61
What type of fatty acids have straight chains that can be tightly packed?
Saturated fatty acids
## Footnote
Saturated fatty acids are more efficient for energy storage due to their tight packing.
62
What is the effect of tight packing in saturated fatty acids on their melting point?
Higher melting point
## Footnote
The tight packing increases intermolecular forces, resulting in a higher melting point.
63
At what temperature do saturated fats typically exist as solids?
25ºC
## Footnote
Saturated fats are solid at room temperature.
64
What type of fatty acids have kinked chains that cause them to be more loosely packed?
Unsaturated fatty acids
## Footnote
Unsaturated fatty acids can have multiple kinks, making them even more dispersed.
65
What is the result of fewer intermolecular forces in unsaturated fatty acids?
Lower melting point
## Footnote
Less energy is required to separate unsaturated fatty acids due to fewer intermolecular forces.
66
At what temperature do unsaturated fatty acids usually exist as liquids?
25ºC
## Footnote
Unsaturated fatty acids remain liquid at room temperature.
67
Fill in the blank: Saturated fatty acids are typically _______ at room temperature.
solid
## Footnote
This is due to their higher melting point.
68
Fill in the blank: Unsaturated fatty acids are typically _______ at room temperature.
liquid
## Footnote
This is due to their lower melting point.
69
True or False: Poly-unsaturated fatty acids have more kinks than mono-unsaturated fatty acids.
True
## Footnote
More kinks lead to even more dispersion in their structure.
70
What are triglycerides in adipose tissues used for?
Energy storage and thermal insulation
## Footnote
Triglycerides provide a mechanism for long-term energy storage in animals.
71
How much energy can triglycerides store compared to carbohydrates?
Roughly twice as much energy per gram
## Footnote
This makes triglycerides a more efficient energy source.
72
Do triglycerides contribute to the osmotic pressure of the cell?
No, they do not contribute to osmotic pressure
## Footnote
This is because triglycerides are non-polar.
73
Why are triglycerides more difficult to digest?
They can only be broken down aerobically
## Footnote
This digestion process limits their accessibility as an energy source.
74
What is a consequence of the hydrophobicity of triglycerides?
They cannot be easily transported
## Footnote
This characteristic affects their role in energy metabolism.
75
What type of energy storage are triglycerides more suitable for?
Long-term energy storage
## Footnote
In contrast, carbohydrates (glycogen) are more suitable for short-term energy storage.
76
What property of triglycerides makes them effective thermal insulators?
Triglycerides have low thermal conductivity
## Footnote
This means they have a limited capacity to conduct heat.
77
What adaptation do mammals in cold or aquatic environments have for thermal insulation?
Thick layers of subcutaneous fat
## Footnote
This helps insulate their internal organs against cold exposure.
78
What are phospholipids?
Key structural components of all cell membranes responsible for the formation of lipid bilayers
## Footnote
Phospholipids are essential for maintaining the integrity and functionality of cell membranes.
79
What is the composition of a phospholipid?
A polar head (hydrophilic) composed of a glycerol and a phosphate molecule, and two non-polar tails (hydrophobic) composed of fatty acid chains
## Footnote
The polar head interacts with water, while the tails do not.
80
What does it mean for phospholipids to be amphipathic?
They contain both hydrophilic (water-loving) and lipophilic (fat-loving) regions
## Footnote
This unique property allows them to form bilayers in aqueous environments.
81
How do phospholipids arrange themselves in a bilayer?
The two hydrophobic tails are shielded from the surrounding polar fluids by the outward facing hydrophilic heads
## Footnote
This arrangement is crucial for creating a barrier that separates the interior of the cell from the external environment.
82
What holds the phospholipid bilayer together?
Weak hydrophobic associations between the non-polar tails
## Footnote
This weak interaction contributes to the fluid and flexible nature of the bilayer.
83
True or False: Phospholipids are only hydrophilic.
False
## Footnote
Phospholipids have both hydrophilic and hydrophobic regions.
