Brainscape's Knowledge GenomeTM

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


See full index

Biology water > 1.1 > Flashcards

1.1 Flashcards

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

What are the 5 molecules that make up living organisms?

A

Water, carbohydrates, protein, lipids, nucleic acids

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

What are lipids?

A

Fat & oils

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

What are nucleic acids?

A

DNA and RNA

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

What elements make up 99% of the atoms in living organisms?

A

Hydrogen, carbon, oxygen, nitrogen

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

What are micronutrients

A

Elements needed in trace amounts

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

What can carbon atoms join to form?

A

Chain and ring structures, which are essential to life

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

What are complex compounds of carbon called?

A

Organic compounds

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

What do organic molecules have?

A

Carbon - hydrogen bonds. E.g CH4

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

What are organic compounds?

A

Molecules of life, e.g carbohydrates, proteins and lipids. Complex compounds of carbon

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

What are inorganic compounds?

A

Compounds which don’t have carbon-hydrogen bonds

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

What is an ion?

A

An atom or group of atoms which has lost or gained 1 or more electrons

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

What kind of elements present as inorganic ions?

A

Many key elements, essential for cell metabolism are present as inorganic ions.

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

What is magnesium’s biological role?

A

Constituent of chlorophyll, so essential for photosynthesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is iron’s biological role?

A

Part of haemoglobin, which transports oxygen in red blood cells.

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

What is nitrate’s biological role?

A

Nitrogen is derived from nitrate and it is needed for making nucleotides (ATP, DNA, RNA), and amino acid formation.

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

What is phosphate’s biological role?

A

Making nucleotides like ATP, DNA, RNA. Constituent of phospholipids found in biological membranes. Hardens bones.

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

What is calcium’s biological role?

A

A component of plant cell walls. Hardens bones and teeth. Is a chemical messenger.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the most important biochemical?

A

Water. Without it, life wouldn’t exist on the planet.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Is water polar or non polar?

A

A polar molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a polar molecule?

A

Molecule where the oxygen end of the molecule has negative charge and hydrogen atoms have positive charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a dipole?

A

The uneven distribution of charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is a hydrogen bond formed?

A

When two water molecules are in close contact, the opposing charges attract each other, forming a hydrogen bond.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the attraction between water molecules called?

A

Cohesion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do polar molecules dissolve.

A

Polar molecules can only dissolve polar molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What bond is formed when 2 water molecules are in close contact and the opposing charges attract each other?

A

Hydrogen bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What framework is formed by many hydrogen bonds?

A

Lattice-like framework (stronger than just one hydrogen bond)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Properties of water

A

Solvent, transport medium, chemical reaction site, high specific heat capacity, high latent heat of vaporization, cohesion, surface tension, density, transparent, metabolite.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What does it mean if water is a solvent?

A

Positive and negative parts of water molecule attract other charged particles.
Ion and polar molecules dissolve in water. Non polar molecules like lipids do not dissolve in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What does it mean if water is a transport medium?

A

Lots of water in blood and it transports many dissolved substances around the body.
In plants, minerals dissolved in water transported from roots to leaves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What does it mean if chemical reactions take place in water?

A

Transport of ions and polar molecules allow chemical reactions to take place when particles or molecules meet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What does it mean if water has a high latent heat capacity

A

Lots of heat energy is needed to raise temp of water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Why is high latent heat capacity important in water?

A

Keeps temperature of aquatic environments stable, and allows molecules to work effectively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What does it mean if water has a high latent heat of vaporisation?

A

Because of cohesion, large amounts of heat energy are needed to change water from liquid to vapour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What causes cooling in body?

A

Evaporation of water from our skin (a surface)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is cohesion?

A

Attraction between water molecules. Allows water molecules to be transported up xylem of even the tallest trees.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Surface tension in water

A

At ordinary temperatures, water has the highest surface tension of other liquids. Cohesion of water molecules supports organisms to walk on water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Density of water

A

As ice, water is less dense.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Why is water less dense as ice?

A

Reduces tendency for lots of water to freeze completely, so organisms survive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Why is water transparent?

A

Allows light to pass through, so that aquatic plants and algae can photosynthesise.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What does it mean if water is a metabolite?

A

Takes place in many biochemical reactions. E.g photosynthesis and hydrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are carbohydrates?

A

Organic compounds containing carbon, hydrogen, and oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What do carbohydrates do?

A

Source of energy in plants and animals. Some have structural role in plant cell walls (e.g. cellulose).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are monosaccharides?

A

Small organic molecules called monomers .
Sugars that dissolve easily.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Structure of monosaccharides?

A

Can be straight chain or a ring structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

How are monosaccharides classified?

A

According to the number of carbon atoms in the molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Name of the monosaccharide with 3 carbons? And its function

A

Triose - important in metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Name of the monosaccharide with 5 carbons? And its function

A

Pentose - nucleic acid formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Name of the monosaccharide with 6 carbons? And its function

A

Hexose - Main energy source of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What are isomers

A

Molecules that share the same number of atoms and same chemical formula, but the atoms are arranged differently. E.g. an alpha glucose ring has H above C1 while beta glucose has C1 above H

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What are structural isomers?

A

Isomers with the same molecular formula but atoms are linked in different sequences. E.g glucose and fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What are optical isomers?

A

Isomers with the same molecular formula and are identical in every way except that they’re mirror images of each other. E.g alpha glucose and beta glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What 2 isomers does glucose exist as?

A

Alpha and beta glucose. They share the same number of atoms but the atoms are arranged differently.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

How are disaccharides formed?

A

By joining 2 monosaccharide units by condensation reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What bond joins 2 hexose units together to make a disaccharide?

A

Glycosidic bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Steps of condensation reaction to form a disaccharide

A

1.) 2 hydroxyl (-OH) groups line up alongside each other.
2.) One -OH combines with the H atom of another, forming a water molecule (H2O)
3.) This allows a glycosidic bond/oxygen bridge to form.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

How do you reverse the making of a disaccharide

A

Hydrolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What is hydrolysis?

A

The chemical addition of water to break a chemical bond.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What disaccharide do the monosaccharides glucose+glucose form?

A

Maltose, found in seeds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What disaccharide do the monosaccharides glucose+fructose form?

A

Sucrose, found in fruit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What disaccharide do the monosaccharides glucose+galactose form?

A

Lactose, found in milk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

How to test for reducing sugars?

A

With Benedict’s Reagent.
1. Heat up the solution with Benedict’s.
2. If it’s a reducing sugar it will turn the benedicts from blue to brick red.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

How do reducing sugars turn benedicts from blue to brick red?

A

Because the sugar reduces the blue copper || sulphate to form copper | oxide, which is a brick red precipitate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

How to test for non-reducing sugars with Benedict’s?

A

Non-reducing sugars can’t reduce cupper || sulphate so benedict’s won’t work.
1.) Sucrose must be hydrolysed by boiling in dilute hydrochloric acid.
2.) Glucose and fructose formed.
3.) Acid must be neutralised with sodium hydroxide before testing with benedict’s reagent
4.) Should now give positive result because glucose and fructose are reducing sugars.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What are polysaccharides?

A

Polysaccharides are large molecules called polymers.

65
Q

What are polysaccharides composed of?

A

Composed of many smaller monosaccharides.

66
Q

How are polysaccharides made

A

Monosaccharides (simple sugars, like glucose) joined together by condensation reaction.
When special enzymes bind small monomers together, they create polysaccharides.

67
Q

What is starch?

A

An alpha glucose monomer joined by 1-4 and 1-6 glycosidic bonds.

68
Q

Function and properties of starch

A

For glucose storage in plants.

  • found in plants.
  • storage polysaccharide.
  • compact, so good as energy stores.
  • insoluble, so no osmotic effect.
69
Q

What is glycogen?

A

An alpha glucose monomer joined by 1-4 and 1-6 glycosidic bonds.

70
Q

Function and properties of glycogen

A

For glucose storage in animals.

  • found in animals.
  • storage polysaccharide.
  • compact, so good as energy store.
  • insoluble, so no osmotic effect.
  • highly branched.
71
Q

Why are polysaccharides branched?

A

Because of amylopectin (Alpha glucose monomers joined by 1-6 glycosidic bonds), which are branched

72
Q

Why are polysaccharides coiled?

A

Because of amylose (Beta glucose monomers joined by 1-4 glycosidic bonds), which are branched.

73
Q

What is cellulose?

A

A beta glucose monomer joined by 1-4 glycosidic bonds

74
Q

Function and properties of cellulose

A

For structure of the cell wall.

  • found in plant cell walls.
  • gives high tensile strength to plant cell walls.
  • Hydrogen bonding between cross linking of parallel chain gives structural stability.
  • chains of cellulose grouped to form microfibrils.
  • insoluble.
  • adjacent glucose molecules rotates 180 degrees
75
Q

Why are adjacent glucose molecules in cellulose rotates 180 degrees?

A

Allows hydrogen bonds to form between
-OH groups

76
Q

What is chitin?

A

A beta glucose monomer joined by 1-4 glycosidic bonds

77
Q

Function and properties of chitin

A

For the structure of fungal cell walls.

  • found in fungal cell walls and exoskeletons.
  • tough and insoluble.
  • each glucose molecule has an amino group attached to it.
78
Q

What is the test for starch?

A

Iodine.
A positive test turns iodine from brown to blue/black.

79
Q

What are lipids?

A

Most common types are triglycerides (fats and oils). Like carbohydrates, they contain carbon, hydrogen and oxygen atoms. Very low oxygen content

80
Q

How are triglycerides formed?

A

Formed by condensation reaction between glycerol and fatty acids.
(3 fatty acid chains bond with glycerol by condensation reaction)

81
Q

What bond is formed between glycerol and fatty acids when a triglyceride is made?

A

ester bond

82
Q

What is a fatty acid?

A

organic molecules which have a -COOH group attached to a hydrocarbon tail

83
Q

What forms the backbone of a triglyceride?

A

glycerol (an alcohol)

84
Q

Properties of triglycerides

A
  • non-polar (doesn’t dissolve in water but does in alcohol).
  • hydrophobic
  • no repeating subunits, just glycerol and fatty acids
85
Q

What is an r-group

A

Variable group of atoms on an amino acid. Bonds form between them

86
Q

What is the test for lipids? And how does it work?

A

Emulsion test for lipids.

  1. shake equal volumes of ethanol and water with solution.
  2. If lipids present it would form cloudy emulsion.
    Because ethanol dissolves lipids so lipids come out of solution and make it cloudy
87
Q

Functions of triglycerides

A
  • energy reserve in plants and animals
  • thermal insulator
    -protection of delicate organs.
  • metabolic water source
  • waterproofing
  • low density and buoyancy
  • nerve transmission
  • steroids and cholesterol.
88
Q

Why/how are triglycerides good energy reserves in plants and animals

A

In animals, fat (a triglyceride) is stored under skin and around organs. In plants, triglycerides stored as oils in seeds.
Also is better than carbs because has twice as much energy

89
Q

Why/how are triglycerides good thermal insulators

A

When stored under the skin, it reduces heat loss

90
Q

Why/how are triglycerides good protection?

A

Around delicate organs like kidneys

91
Q

Why/how are triglycerides good metabolic water sources?

A

Produce lots of metabolic water when oxidised. essential for desert animals who don’t drink water and survive on metabolic water from fat intake

92
Q

Why/how are triglycerides low density and buoyancy

A

Fat has low density so that animals float in water. Seeds with oils can be easily dispensed since they’re light

93
Q

Why/how are triglycerides good nerve transmissions

A

Form myelin sheath which seeps up nerve transmission

94
Q

Why/how are triglycerides steroids and cholesterol

A

Steroids (include sex hormones) are lipids. Ring structure, not long chain structure

95
Q

What are unsaturated fatty acids?

A

Fatty acids which have double bonds between neighbouring carbon atoms. Don’t carry maximum possible number of hydrogen atoms.

96
Q

Why do unsaturated fatty acids have a lower melting point?

A

Each double bond causes a kink in the fatty acid chain so it can’t be packed together closely, so it has a lower melting point as it’s easier to change it’s state. E.g. Oils

97
Q

What is it called when unsaturated fatty acids only have one double bond?

A

Monounsaturated

98
Q

What is it called when unsaturated fatty acids have more than one double bond?

A

Polyunsaturated

99
Q

What are saturated fatty acids?

A

Fatty acids which have no double bonds between carbon atoms

100
Q

Why are saturated fatty acids solid?

A

Fatty acids are packed closely together.
E.g. animal lipids like lard.

101
Q

What would multiple fatty acids linked together form?

A

Polymer

102
Q

How is heart disease caused?

A

Caused by build up of fatty deposits in coronary arteries, and high blood pressure

103
Q

Risk factors of heart disease?

A
  • a diet high in saturated fatty acids
  • lack of regular exercise
  • high salt diet
  • age, gender, genetics
  • smoking
104
Q

How are lipoproteins formed?

A

Food is absorbed into bloodstream and lipids & proteins combine to form lipoproteins.

105
Q

Why are low density lipoproteins (LDL’s) produced?

A

If diet is high in saturated fatty acids, they’re produced

106
Q

Why do LDL’s cause harm?

A

They’re deposited on the inner endothelial lining of coronary arteries and build up to form an atheroma

107
Q

What do atheromas do?

A

Narrow coronary arteries and slow blood flow. Reduces oxygen and glucose delivery to the cardiac muscle, which causes angina. Large blood clots can form and block the artery which starves heart muscle of oxygen and glucose. This causes heart attack

108
Q

What forms from a diet rich in unsaturated fatty acids?

A

Forms high density lipoproteins (HDLs) in bloodstream

109
Q

What do HDL’s do?

A

Carry harmful fats to the liver for disposal

110
Q

Higher ratio of HDL:LDL means?

A

Lower risk of cardiovascular and coronary heart disease

111
Q

What are phospholipids?

A

Special types of lipids where 1/3 of the 3 fatty acids are replaced by a phosphate group.

112
Q

Are phosphate groups polar or non polar?

A

Polar so soluble in water

113
Q

Explain the heads and tails of phospholipids

A

Hydrophilic head with a phosphate group, and 2 hydrophobic fatty acid tails

114
Q

How is a micelle formed?

A

In water, the hydrophobic fatty acid tails of phospholipids turn inwards to form a micelle

115
Q

If there is enough phospholipid molecules, what is formed?

A

A bilayer.
Polar/hydrophilic phosphate heads point outwards (in water), hydrophobic fatty acid tails point inwards (away from water)

116
Q

Phospholipid bilayer forms…

A

basis of all cell membranes

117
Q

Compare triglycerides with phospholipids

A
  • T have 3 fatty acid tails, P only have 2 fatty acid tails.
  • T have no phosphate group, P have phosphate group.
  • T are nonpolar, P have polar head and non polar tail.
  • T are completely hydrophobic, P have hydrophilic head and hydrophobic tails.
118
Q

What are proteins

A

Polymers of amino acids that are incredibly important biological molecules. Have many essential and varied functions.

119
Q

What are proteins made up of?

A

Carbon, hydrogen and oxygen atoms (like carbohydrates and lipids)

120
Q

What do all and some proteins contain?

A

Always contain Nitrogen (N). Some contain Sulphur (S) and Phosphorus (P)

121
Q

What is key for a protein to be functional?

A

shape of the protein

122
Q

Functions of proteins?

A
  • build and repair muscles and bones with the amino acids they’re made of.
  • wound healing and tissue regeneration.
  • form structure of tissues and organs for them to work correctly.
  • provide energy when carbohydrates and fat intake are inadequate
  • make antibodies
  • homeostasis
  • muscle contraction and movement
123
Q

Structure of proteins

A

All proteins made up of linear sequences of amino acids. Around 20 different amino acids with different -R groups

124
Q

What does DNA do on an amino acid?

A

DNA decides what goes where/positions the amino acids

125
Q

General amino acid structure

A

All amino acids have a central carbon atom with amino group (-NH2) and carboxyl group (-COOH) on either side. The 3rd bond is Hydrogen and the 4th bond is an r-group

126
Q

What is the simplest amino acid

A

Glycine.
The r group is just a hydrogen atom

127
Q

What are essential amino acids

A

Amino acids that can only be obtained from our diet

128
Q

What are non essential amino acids

A

Amino acids that can be synthesised by our bodies

129
Q

What do peptide bonds do?

A

Link amino acids together to form dipeptides and polypeptides

130
Q

How do you turn polypeptides into proteins

A

Polypeptides can be folded to make proteins

131
Q

How are peptide bonds formed?

A

Caused by a condensation reaction between (-COOH) carboxyl group and (-NH2) amino group. Water is produced

132
Q

How is a dipeptide molecule formed?

A

2 amino acids being joined with a peptide bond

133
Q

How are polypeptides formed?

A

Many amino acids joined together through polymerisation

134
Q

What are polymers?

A

Long molecules made of repeating subunits (monomers)

135
Q

How are polymers formed?

A

Monomers added 1 at a time by condensation reaction to form a long molecule

136
Q

What is primary structure?

A

The order and sequence of amino acids in a polypeptide chain

137
Q

What determines the sequence of amino acids

A

DNA determines the sequence of amino acids. 1 gene codes for 1 polypeptide

138
Q

What is secondary structure?

A

The folding of a primary structure to form an alpha helix shape

139
Q

How is secondary structure alpha helix formed?

A

Formed due to hydrogen bonding between R-groups. Hydrogen bonds twist and fold polypeptides, forming alpha helix shape or beta pleated sheet,

140
Q

What is tertiary structure?

A

The further folding of secondary structure to create a 3D globular shape.

141
Q

How is shape of tertiary structure maintained?

A

Maintained by disulphide, ionic, covalent hydrophobic, and hydrogen bonds formed between R-groups

142
Q

What structure do enzymes have and why?

A

Tertiary structure. The bonds maintain the shape of the active site

143
Q
A
144
Q

What is quaternary structure?

A

Combination of 2 or more polypeptide chains in secondary or tertiary form

145
Q
A
146
Q

How are large complex molecules formed with quaternary structures

A

Some are associated with non protein groups which form large complex molecules. E.g haemoglobin

146
Q

Structure of haemoglobin

A

4 polypeptide chains associated with non protein haem groups

147
Q

Functions of globular proteins (tertiary and quaternary)

A

Enzymes, antibodies, hormones

148
Q

Structure of globular proteins

A

Compact and folded into spherical molecules

149
Q

Are globular proteins soluble or insoluble

A

Soluble in water,

150
Q

What do fibrous proteins (secondary) do?

A

Perform structural functions

151
Q

Structure of fibrous proteins?

A

Consist of polypeptides in parallel chains/sheets with numerous cross linkages to form long fibres

152
Q

Properties of fibrous proteins?

A

Insoluble in water,
strong,
tough

153
Q

Structure of a single fibre?

A

3 identical polypeptide chains twisted together. Linked by hydrogen cross-bridges

154
Q

What do hydrogen cross bridges do?

A

Make structure very stable

155
Q

What is collagen and what does it do?

A

Fibrous protein/single fibre. Provides properties needed in tendons

156
Q

What is the test for peptide bonds? (between amino acids of polypeptides/proteins)

A

Biuret test.

If protein is present, biuret turns from blue to violet/purple. Intensity of the colour directly proportional to the protein concentration/number of peptide bonds

157
Q

Why does biuret change from blue to purple?

A

Copper || ion forms the violet/purple coloured complex in alkaline solution

158
Q

What is used to measure change in colour and why?

A

Colorimeter. Because at low concentrations, colour change may not be obvious so colorimeter is used to measure change.

Biology water (2 decks)

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