Molecules Flashcards
What is a polar molecule?
A molecule with slight charge
What is a non-polar molecule?
A molecule with zero charge
What is a polar covelent bond and how is it formed?
Slightly positively charged ions attract to slightly negatively charged ions and share electrons, this forms the bond and happens due to a force of attraction.
What are the 7 properties of water?
- Adhesion
- Cohesion
- High specific heat capacity
- High heat of vaporization
- High heat of Fusion
- Versatile solvent
- Higher density as a liquid than as a solid
What is cohesion?
When two water molecules attract to each other and create hydrogen bonds, this happens due to O- and H+ attracting
What is adhesion?
When a molecule of water attracts to an other molecule and creates a hydrogen bond, this happens due to a polar end of the water attracting the opposing polar end of the other ion
How is cohesion and adhesion used?
- Surface tension, water does not break at the surface due to hydrogen bonds, this allows some insects to walk on the water,
- Carrying water and mineral ions up xylems, the water attaches to each other (cohesion), and pulls itself up the wall of the xylem (adhesion)
- Capillary action, adhesion in a narrow tube, this cause a meniscus which can me measured for volume
What is Specific heat capacity?
The amount of energy it takes to raise 1 gram by 1°C
Why is high specific heat capacity good in water?
- Temperature does not change quickly*
- This means we keep a stable body temperature as out body has time to make adjustments to cool down or heat up depending on a changing weather,
- Also means that life in water will have time to adapt to their change in environment as the weather gets hotter
What is a Versatile solvent?
Water has the capabilities of dissolving most solutes
Why is water being a versatile solvent beneficial?
- In plants, mineral ions dissolve in water and are carried up in the xylems to the rest of the plant
- In animals, water makes up a large proportion of our cells and can transport important nutrients.
What is Heat of vaporization?
The energy it takes to turn a liquid into a gas or gas to liquid/ change state
- In water: 540cal/g at 100°C
Why is a high heat of vaporization important?
- In order to cool down, our bodies use excess energy to evaporate sweat (predominantly water) on the surface of our skin, this energy is lost to the surroundings as the water vapor leaves our skin
Why does water have a higher density than ice?
When water freezes, the lattice structure it forms when it changes state has the water molecules spread further apart than when the water was a liquid. Since the water molecules are closer together as a liquid, its density is greater
Why is it important for some animals that water has a higher density than ice?
A layer of ice will float atop the body of water so the fish are free to live unfrozen underneath
What type of bonds form from water to water?
Hydrogen bonds
What type of bonds form between the OH+ and H- in water molecules?
Polar covalent bonds
What is a calorie?
The amount of energy it takes to raise 1 g of WATER by 1°C
What does hydrophobic mean?
When something is hydrophobic it is non-polar, so it does not attract to the polar water molecules
What does Hydrophilic mean?
When a molecule is hydrophilic it is polar, so it does attract to polar water molecules
What is electronegativity?
The attractive force that an atomic nucleus exerts on electrons.
If a molecule is electronegative it is charged
Where is another example of where hydrogen bonds are used?
Bonds between base pairs in a nucleotide
Why does water have a high specific heat capacity?
The energy emitted onto the water does not excite the molecules and cause them to move quicker, instead, the energy is used to attempt to break the hydrogen bonds between water molecules. So the water resists temperature change
What is a macromolecule?
larger molecules, also known as polymers.
- The polymers are made of monomers that bond together
- ‘Poly’ means many
- ‘Mer’ means unit
What are the 4 functional groups?
- Hydroxyl group (OH)
- Carboxyl group (COOH)
- Phosphate group (P)
- Amine Group (NH2)
What is a condensation reaction?
Removal of a water molecule when bonding two monomers together, creating a polymer with a hydrogen bond and a biproduct of water
What is a hydrolysis reaction?
The addition of water to a polymer, breaking it down back into its original monomers with the water distributed between the two monomers
What is another name for a condensation reaction?
A dehydration reaction
What is the functional group of Carbohydrates?
C:H:O (1:2:1)
What are examples of Carbohydrates?
- Glucose
- Starch
- Cellulose
- Ribose
- Lactose
What is the bond created in a Carbohydrate polymer?
Glycosidic bond
What is the function of Carbohydrates?
Fast energy, structure, identification
What is the Carbohydrate monomer called?
Monosaccharides
What is the chemical formula for the structure of a monosaccharide?
C{n}H{2n}O{n}
What is the differences between Ribose and Deoxyribose?
- In ribose there is a hydroxyl group at C2
- Ribose is single stranded so less stable
- Deoxyribose is double stranded so more stable
What are the similarities between Ribose and Deoxyribose?
- Both are pentoses/ 5 Carbon sugars
What is the structure of cellulose?
- Thick long chain, so very tough
- β glucose
What is cellulose used for?
The cell wall in plants
What is the structure of Starch?
- Slightly branched
- α glucose
What is starch used for?
Energy storage in plants
What is the structure of glycogen?
- highly branched
- α glucose
What is glycogen used for?
Energy storage in humans
How many times can a covalent bond occur between the same molecules?
3
- Single bond (share 1 electron)
- Double bond (share 2 electrons)
- Triple bond (share 3 electrons)
Why are lipids not soluble in water?
They are bonded with non-polar covalent bonds, they are hydrophobic so avoid interaction with water
What happens when the hydrophobic lipids move away from the polar water molecules?
They huddle together amongst their non-polar lipid counterparts and from weak interactions called van der waals hold them together
What is the chemical function for Lipids?
CHO
What are some examples of Lipids?
- Fats
- Oils
- Cholesterol
- Hormones
What is the bond between lipid monomers called?
Ester
What are the functions of a Lipid?
- Long term energy storage
- Chemical messages
- Cell membranes
What is a Lipid monomer called?
Triglyceride, but some lipids do not have this base monomer
What do triglycerides consists of?
- 3 fatty acids, non-polar hydrocarbon chain attached to a polar carboxyl group (-COOH)
- 1 Glycerol, An alcohol with 3 hydroxyl (-OH) groups
How many condensation reactions are needed when synthesising a triglyceride
3
What is the difference between a saturated and unsaturated fat?
- A saturated fat has its Carbons bonding to the maximum number of hydrogens, this creates a stable and strong molecule
- An unsaturated fat can form double or triple bonds between Carbons , this creates a weaker molecule as there is more space
- A saturated fat is solid at room temp
- An unsaturated fat is liquid at room temp
- Saturated: C{4}H{9}
- Unsaturated: C{4}H{7}
What quality does fatty acids have that allow it to create the cell membrane?
They are amphipathic
- this means it has a polar and non-polar end
- Polar head
- Non-polar tail
- This creates a semi-permeable membrane
What molecule is mainly used in the cell membrane?
Phospholipids
How do the structures of Saturated and Unsaturated lipids compare?
- The saturated lipids are a straight chain, moving downwards in a zig-zag pattern,
- While the unsaturated does also follow a zig-zag pattern, the bonds are irregular in shape in some places so create bends in the chain, making it look more like an L
- Saturated: ‘I’ Shape
- Unsaturated: ‘L’ shape
Which direction do the head and tail of a phospholipid face in the cell membrane?
The tails face each other inwards, while the heads face outwards towards the aqueous solution
What is the chemical functional of a Protein?
CHON
What are some examples of Proteins?
- Hemoglobin
- Catalase
- Albumin
- Keratin
What is the bond called that forms between two protein monomers?
Peptide bond
What are the functions of Proteins?
- Structure
- Enzyme digestion
- Transport
- Storage,
- Movement
What is the monomer of Proteins?
Amino acid
What is the atomic structure of a protein monomer?
- Carbon in the middle
- H above
- R group below
- Amino group to the left (NH{2})
- Carboxyl group to the right (COOH)
- Double bond on C=O
How does a dehydration reaction happen in a Protein?
- An H is taken from the amino group and bonds with a OH from the carboxyl group of another amino acid
- This creates H{2}O and is removed from the two monomers as a biproduct
- Then a peptide bond is formed between the two amino acids to make a protein
What are the 4 stages of structure in a Protein?
- Primary
- Secondary
- Tertiary
- Quaternary
What is the primary structure of a Protein?
The arrangement of the amino acid chain
What is the secondary structure of a Protein?
Repeated spatial patterns of a protein as a result of hydrogen bonding between amino acids along the chain
- There are two types of folds:
- α helix
- β pleated sheet
What is the tertiary structure of a Protein?
The chain is bent and folded; results in a 3D shape
- The hydrophobic amino acids tend to converge towards the inner part of the protein and create weak interactions,
- The hydrophilic amino acids tend to move to the edge of the protein towards other polar molecules like water
What bonds are used in the tertiary structure of a Protein?
- Disulfide bridges
- Hydrogen bonds
- Hydrophobic interactions
- Ionic interactions
What is the quaternary structure of a Protein
Two or more polypeptide chains bind together using hydrophobic and ionic interactions, and hydrogen bonds,
- These small changes create small tweaks in the Proteins structure and function
Is it possible to have both an alpha helix and a beta pleated sheet in the same protein?
Yes
Describe the basic structure and function of hemoglobin.
- Quaternary structure
- Made of 4 subunits, 2 pairs of different proteins:
- Alpha helix and Beta pleated sheets
- Transports oxygen in the blood
- Carries oxygen like a bowl
Describe the function of Lactase and why it is specified for its function.
- Enzyme
- Breaks down lactose
- Lactose is a substrate that is specific to the active site of Lactase, this means that the structure of lactase is unique to host the break down of lactose alone.
What causes an enzyme to denature?
- Temperature
- Change in PH
- Concentration of H+ ions
- High concentration of polar substances
- Non polar substances
What is denaturing?
When an enzyme loses its shape due to an environmental change, this means it does not have its active site so cannot carry out its function,
Is denaturing reversible?
Yes by cooling or restoring optimal conditions, all the information needed for the protein to restructure itself is in the primary structure
Where does the information for the secondary and tertiary structure reside?
The primary structure/ order of amino acids
What is the chemical structure of Nucleic acids?
CHONP
What are examples of Nucleic acids?
- RNA
- DNA
- ATP
What is the bond called between two Nucleic acid monomers?
Phosphodiester
What is the function of Nucleic acids?
Genetic information
What is the monomer for Nucleic acids?
Nucleotides
How does structure affect function in Nucleic acids?
- The bonds between 2 nitrogenous bases in DNA have weak hydrogen bonds so they can be opened and accessed easily for processes such as protein synthesis,
- Base pairs match up with 1 pyrimidine base and 1 purine. if either of these changed the DNA strand would be too thick or thin
- The structure of the base pairs make the DNA straight, this allows the DNA to be created into a made properly
What does DNA Stand for?
Deoxyribonucleic acid
What does RNA stand for?
Ribonucleic acid
What is the difference between deoxyribose and ribose?
Deoxyribose lacks oxygen while ribose has an oxygen at C2
What makes up a nucleotide?
- Base
- Pentose sugar
- Phosphate group
What is a nucleoside?
A nucleotide with out a phosphate group:
- Base
- Pentose sugar
What is a pyrimidine?
A single ringed base, looks like one carbon ring
What is a Purine?
A double ringed base, looks like two carbon rings
What are the purines in DNA?
- Adenine
- Guanine
What are the pyrimidines in DNA/RNA?
- Cytosine
- Thymine
- Uracil
What bases pair in DNA, and what is different in RNA?
- Adenine and Thymine (A-T Austin Texas)
- Guanine and Cytosine
- Adenine and Uracil bond in RNA
In what process is a phosphodiester created?
Condensation reaction
What is the heat of fusion?
The energy needed for a liquid to turn to a solid or solid to liquid/ change state
What is a sphere of hydration?
When polar molecules are surrounded by polar water molecules, this dissolves the substance in the water
