Brainscape's Knowledge GenomeTM

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


See full index

biology YEAR1 > B1- BIOLOGICAL MOLECULES > Flashcards

B1- BIOLOGICAL MOLECULES Flashcards

3.1.1 Monomers and polymers 3.1.2 Carbohydrates 3.1.3 Lipids

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

3.1.1 Monomers and polymers

What are Monomers? Include examples

A

Monomers are small units which are the components of larger molecules.
Examples:
- monosaccharides (glucose, fructose and galactose)
- amino acids
- nucleotides

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

3.1.1 Monomers and polymers

What are Polymers? Include examples

A 
Polymers are molecules made from a large number of monomers joined together.
Examples:
- DNA
- RNA
- Proteins
- Polysaccharides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

3.1.1 Monomers and polymers

What is a Condensation Reaction?

A

A condensation reaction joins two monomers together whereby a water molecule
is eliminated

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

3.1.1 Monomers and polymers

What is a Hydrolysis Reaction?

A

A hydrolysis reaction breaks a chemical bond between two molecules by the use of a water molecule

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

3.1.2 Carbohydrates

What are Carbohydrates?

A

Carbohydrates are molecules which consist only of carbon, hydrogen and oxygen and they are
long chains of sugar units called saccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3.1.2 Carbohydrates

What are monosaccharides? What are the three most common examples?

A

Monosaccharides are the simplest carbohydrates and are monomers from which larger
carbohydrates are made. Glucose, galactose and fructose are common monosaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

3.1.2 Carbohydrates

What is the reaction between two monosaccharides. What is the bond formed?

A

A condensation reaction occurs between two monosaccharides. The bond formed is called a (1,6) or (1,4) Glycosidic Bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

3.1.2 Carbohydrates

Name the three Monosaccharides What is the molecular formula?

A

Glucose, Fructose and Galactose.

Molecular formula: C(6)H(12)O(6)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

3.1.2 Carbohydrates

What are disaccharides?

A

Disaccharides are formed when two monomers react together.

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

3.1.2 Carbohydrates

How are these disaccharides formed? :

  • Maltose
  • Sucrose
  • Lactose
A

Maltose: two glucose molecules
Sucrose: Glucose + Fructose
Lactose: Glucose + Galactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

3.1.2 Carbohydrates

what is glucose?

A

glucose is used in respiration and comes from carbohydrates we ingest and digest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

3.1.2 Carbohydrates

What are the two isomers of glucose? Draw the structures

A

Alpha and Beta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

3.1.2 Carbohydrates

What is a polysaccharide? Give examples

A 
a carbohydrate whose molecules consist of a number of sugar molecules bonded together.
Examples:
- Starch
- Cellulose 
- Glycogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

3.1.2 Carbohydrates

Describe the structure and function of Starch

A

Starch is the storage polymer of α glucose in plant cells

  • insoluble so will not affect cell water potential
  • compact so a lot of energy can be stored in a small space

Starch is a mix of 2 different polysaccharides:
1 ) Amylose: a long chain of α-glucose monomers joined by 1,4-glycosidic bonds. The chain coils in a spiral shape, held together by hydrogen bonds. This shape makes starch well suited to energy storage as it is compact, so takes up little space in the cell, and not very soluble in water, so does not affect the water potential of the cell.
2 ) Amylopectin: branched chains of α-glucose monomers joined by 1,4-glycosidic bonds and 1,6-glycosidic bonds.
- The 1,6-glycosidic bonds form the links which make branches.
- branches mean there are many glucose molecules accessible on the end of chains which can be easily broken off by hydrolysis for use in respiration. Therefore amylopectin can provide a rapid supply of energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

3.1.2 Carbohydrates

Describe the structure and function of Cellulose

A

Cellulose is a component of cells walls in plants
- is composed of long, unbranched chains of
beta glucose (β) which are joined by glycosidic bonds
- Microfibrils are strong threads which are
made of long cellulose chains running parallel to one another that are joined together by
hydrogen bonds forming strong cross linkages.
- important in stopping the cell wall
from bursting under osmotic pressure. This is because it exerts inward pressure that stops the
influx of water. This means that cells stay turgid and rigid, helping to maximise the surface area
of plants for photosynthesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

3.1.2 Carbohydrates

Describe the structure and function of Glycogen

A

Glycogen is the main energy storage molecule in animals
- formed from many molecules of
alpha glucose (α) joined together by 1, 4 and 1, 6 glycosidic bonds
- has a large number of side
branches meaning that energy can be released quickly as enzymes can act simultaneously on
these branches.
- it is a relatively large but compact molecule thus maximising the amount of energy it can store.
- being insoluble means it will not affect the water
potential of cells and cannot diffuse out of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

3.1.2 Carbohydrates

Which biochemical tests are suitable for these samples:

  • reducing sugars
  • lipids
  • non-reducing sugars
  • starch
  • protein
A
  • reducing sugars= Benedicts Test
  • lipids- Emulsion Test
  • non-reducing sugars- Benedicts Test
  • starch- Iodine Test
  • protein- Buiret Test
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

3.1.2 Carbohydrates

What is the test for lipids? What is the method?

A

Emulsion test for Lipids

  1. Dissolve sample in ethanol
  2. Add an equal volume of water and shake the test tube
  3. A positive result will produce a milky white emulsion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

3.1.2 Carbohydrates

What is the test for reducing sugars? What is the method?

A

The Benedict’s test for reducing sugars: -

  1. Heat the test sample with Benedict’s Reagent.
  2. Observe the colour change.
  3. A brick red precipitate indicates the presence of a reducing sugar.
20
Q

3.1.2 Carbohydrates

What is the test for non- reducing sugars? What is the method?

A

The Benedict’s test for non-reducing sugars: -

  1. Heat the test sample with dilute hydrochloric acid.
  2. Neutralise the test sample by adding sodium hydrocarbonate.
  3. Heat the test sample with Benedict’s Reagent.
  4. Observe the colour change.
  5. A brick red precipitate indicates the presence of a reducing sugar.
21
Q

3.1.2 Carbohydrates

What is the test for starch? What is the method?

A

The Iodine Test for Starch:

  1. To test for the presence of Starch in a sample…
  2. Add 10 drops of Iodine in Potassium Iodide Solution to the test sample.
  3. Observe the results: Positive results will show a Purple [blue-black] colour.
22
Q

3.1.2 Carbohydrates

What is the test for protein? What is the method?

A

The Biuret Test for Proteins
- Add 2 cm3 of the liquid food sample* to a clean, dry test tube
- Add 2 cm3 of Biuret Reagent.
Repeat steps the steps above with de-ionized water to prepare a negative control and with albumin (egg white) to prepare a positive control.
- Shake well and allow the mixture to stand for 5 minutes

23
Q

3.1.2 Carbohydrates

What are the three main reducing sugars?

A

Glucose

Fructose

Lactose

24
Q

3.1.2 Carbohydrates

What is the main non-reducing sugar?

A

Sucrose

25
Q

3.1.3 Lipids

What are Lipids?

A

Lipids are biological molecules made of carbon, hydrogen and oxygen. They don’t dissolve in water (hydrophobic molecule) and don’t form polymers.

26
Q

3.1.3 Lipids

What are the main types of Lipids?

A

triglycerides and phospholipids.

27
Q

3.1.3 Lipids

What are Triglycerides? What is the bond formed?

A

Triglycerides are formed by the condensation of one molecule of glycerol and three molecules of fatty acid. An ester bond is formed after the condensation reaction.

28
Q

3.1.3 Lipids

What is the difference between saturated and unsaturated fatty acids?

A 
Saturated:
BOND- contain only single carbon bonds
STRUCTURE- straight chain molecule
MELTING POINT- higher melting point which means it is a solid at room temperature 
LOCATION- found in animal fats
Unsaturated:
BOND- contain carbon to carbon double bonds
STRUCTURE- linked molecule
MELTING POINT- lower melting point 
LOCATION- found in plant oils
29
Q

3.1.3 Lipids

How is a triglyceride related to its function?

A
  • High number of carbon-hydrogen bonds therefore they are an excellent energy store
  • A low mass to energy ratio meaning that they are a good storage molecule, with a lot of
    energy being stored in a small volume. This is beneficial for animals as it is less mass to move
    around
  • Insoluble in water therefore no effect on osmosis in the cells
30
Q

3.1.3 Lipids

What is the functions of lipids?

A

source of energy- release twice the amount of energy as carbohydrates

waterproofing- lipids are insoluble in water therefore are useful for waterproofing

insulation- fats are slow conductors of heat and when stored beneath the body surface help to retain heat. The also act as an electric insulator in the myelin sheath of a plant cell

protection- fat is often stored around the delicate organs, such as the kidney

31
Q

3.1.3 Lipids

What is a Phospholipid?

A

A Phospholipid is similar to lipids however the fatty acid molecules is replaced by a phosphate molecule.

32
Q

3.1.3 Lipids

Compare a fatty acid molecule (triglycerides) and a phospholipid

A

(s) both have glycerol backbone
(s) both contain the elements C, H and O
(s) both formed by condensation reaction
(d) Triglyceride has one glycerol and three molecules of fatty acid whereas Phospholipid has one glycerol, two fatty acid molecules and a phosphate group
(d) FAs are hydrophobic (repel water) whereas PLs are hydrophilic (attract water)

33
Q

3.1.3 Lipids

What is the relationship between phospholipids and water?

A

A molecule thats has two ends which act differently is said to be ‘polar’.

  • A hydrophilic ‘head’- interacts with and attracted to water (not fat)
  • A hydrophobic ‘tail’- orients itself away from water but mixes readily with

Polar phospholipid molecules position themselves in water so that the hydrophilic head is close to the water ads possible whilst the hydrophobic tail is far away from the water as far as possible.

34
Q

3.1.3 Lipids

How is a phospholipid related to its function?

A
  • the hydrophilic phosphate heads help the phosphate molecule to hold at the surface of the cell membrane.
  • the hydrophilic tail
35
Q

3.1.3 Lipids

What is the similarities and differences between carbohydrates and lipids?

A

Both carbohydrates and lipids have the same function which is to store energy.

  • Carbohydrates and lipids both contain carbon (C), hydrogen (H), and oxygen (0)
  • Carbohydrates are used for energy (glucose).
  • Fats are used for energy after they are broken into fatty acids.
36
Q

3.1.3 Lipids

What is the relation between carbohydrates and lipids?

A

The phospholipid structure allows them to combine with carbohydrates to form glycolipids within the cell surface membrane. This is important in cell recognition

37
Q

3.1.4 Proteins

What are proteins? What molecules does it contain?
Draw the general structure

A

Amino acids are the monomers from which proteins are made.

Amino acids contain:

  • central carbon atom
  • an amino group (NH2)
  • carboxylic acid group
  • variable R group
38
Q

3.1.4 Proteins

What bond forms when two amino acids react?

A

A peptide bond

39
Q

3.1.4 Proteins

What are the two types of polypeptide bonds? What’s the difference?

A
  • Dipeptides are formed by the condensation of two amino acids.
  • Polypeptides are formed by the condensation of many amino acids.
40
Q

3.1.4 Proteins

How many amino acids is there? How do they differ?

A

20

They differ by R group

41
Q

3.1.4 Proteins

How do dipeptides and polypeptides form?

A
  • Condensation reaction forms a peptide bond (between amin group and carboxyl group) and eliminates a water molecules
42
Q

3.1.4 Proteins

Define PRIMARY structure of a protein

A
  • order and number of amino acids in a protein

- determines the proteins function in the end

43
Q

3.1.4 Proteins

Define SECONDARY structure of a protein

A

Three secondary structure is the shape that the chain of amino acids form
- either alpha helix or beta pleated sheet

44
Q

3.1.4 Proteins

Define TERTIARY structure of a protein

A

• Tertiary structure of proteins is the 3D shape of the protein and is formed from further
twisting and folding. A number of different bonds maintain the structure, these are:

  • Disulfide bridges - interactions between the sulfur in the R group of the amino acid cysteine these are strong and not easily broken.
  • Ionic bonds - form between the carboxyl and amino groups that are not involved in
    the peptide bond. They are easily broken by pH and are weaker than disulfide
    bridges.
  • Hydrogen bonds - numerous and easily broken
45
Q

3.1.4 Proteins

Difference between Carbohydrates, Lipids and Proteins

A

Carbohydrates and Lipids contain the elements Carbon, Hydrogen and Oxygen
vs
Proteins contain the elements Carbon, Hydrogen, Oxygen, and Nitrogen

Starch and cellulose found in plants
vs
Glycogen found in animals

Glycogen and starch monomers are alpha glucose
vs
Cellulose monomer is beta glucose

Starch and Glycogen coiled structure
vs
Cellulose straight

46
Q

3.1.4 Proteins

Define QUATERNARY structure of a protein

A

Proteins consisting of more than one amino acid chain

- may be non protein (prosthetic groups) within polypeptide chain

biology YEAR1 (3 decks)

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