Unit 2- Molecules of Life ✅

Explain the properties of carbon that allow for the formation of diverse compounds upon which live is built

• Carbon forms covalent bonds with C,H,O,N,P,S

• Forms 4 covalent bonds with other atoms

• Strong and stable bonds → can for chains and rings

• Double, Triple, single bond

Draw a simple diagram to show the relationship between monomers, polymers, water, energy , hydrolysis, and condensation reactions

Outline 4 key functions of proteins. Provide named examples of each.

Function	Description	Examples
Structural	Structural role in animal tissue	Keratin, collagen, actin, myosin, histones
Chemical/Metabolic	Enzymes are proteins required to speed up chemical reactions	DNA polymerase, Rubisco
Signaling	Hormones, neurotransmitter receptors, glycoproteins	Insulin, dopamine receptors.
Membrane transport	Channels pumps	Na + channel

What elements do proteins contain

CHONS

Draw generalized structure of an amino acid

How many different amino acids are there and describe how they differ

• There are 20 different amino acids

• Differ in terms of R group

What is the difference between non-essential and essential amino acids

• Non essential can be produced by the body from other amino acids or the breakdown of proteins

• Essentials can not be produced by the body, therefore they must be eaten. Important for growth, repair, and maintenance of tissue and organs.

Explain how there is essentially an infinite number of possible peptide chains.

• 20 different amino acids

• Polypeptide chains can be 3-1000s of amino acids long

Explain how the chemical diversity of R-Groups of amino acids leads to diversity in protein form and function

• R groups give amino acids “unique properties”

• Based on properties they interact with each other. 

• If 2 amino acids in the same chain attract/repel each other it will change the confirmation of the polypeptide → results is chang of protein shape

• Interactions stabilize the protein

• Influence protein function and position in membrane

Define denaturation

A change to the configuration of a protein as a result if R group interaction being disrupted → results in disruption of protein function

Explain the effect of PH and temperature on protein structure.

If PH or temp exceed the proteins optimum range, it will result in the denaturation of the protein 

Denaturation can be reversible (warmed milk) or irreversible (fried egg) 

PH	Every protein has an optimum PH PH causes changes in intramolecular bonds Exl. Digestive enzymes have different PH depending on location in the gut.
Temp	Vibrations from temp break inner/intramolecular bonds and interactions within the molecule  Physical properties change Ex. Liquid egg albumin → white solid and enzyme activity

Compare the structure of globular and fibrous proteins, and explain how their structure help give rise to their functions

Structure	Function
Fibrous  Consists of parallel polypeptides linked together Insoluble in H2O Structural role Ex. collagen, keratin, muscle fibers	Collagen as example Main component in connective tissue in animals 3 polypeptide chains twisted together → elongated shape Strong and flexible to help support tissue
Globular - Consists of polypeptides folded in spherical shape - Structure determine function, position in membrane, and solubility Ex. insulin. Enzymes, hormones, antibodies	Insulin as example Compact globular structure Binds to receptor on cell to allow glucose to enter Hydrophilic exterior to allow transport in blood.

Explain the 4 levels of protein structure.

Primary structure

• Sequence and order of amino acids determines 3D shape 

• Proteins have precise/predictable shape based on primary structure

• Covalent peptide bond

  

Secondary Structure

• Formation of repeating patterns with in polypeptide

• Alpha helix

• Beta pleated sheets

• H bonds between carboxyl and amino groups

Tertiary structures

• Further folding of polypeptides (r group interactions)

• Hydrophobic amino acid cluster in the core of globular proteins 

• Hydrophilic amino acids are on the outside

Bonding within one polypeptide chain:

• Hydrogen bonds

• polar/non-polar interactions

• +/- ionic interactions

• hydrophobic/hydrophilic interactions

• disulphide bridges

• 

Quaternary structures

• When multiple tertiary polypeptide chains come together and the addition of non-protein components

  Bonding between 2+ polypeptide chains:

  • disulphide bridges

  • hydrophobic/hydrophilic interactions

  • polar/non-polar interactions

  • +/- ionic interactions

  • Hydrogen bonding

  

  Conjugated proteins → amino acid + non protein component 

  Ex. hemoglobin 

  Non conjugated proteins 

  → only amino acid components 

  Ex. Insulin 

  
  
  

Explain the effect of polar and non polar amino acids on tertiary structure of proteins

• Hydrophobic amino acids cluster in the core of globular proteins.

• Hydrophilic amino acids are on the outside

Distinguish between the quaternary structure non-conjugated and conjugated protein , provide an example for each

• Non-conjugated proteins are made of amino acids only.

  • Example of conjugated protein: Insulin and collagen

• Conjugated proteins are made of amino acids PLUS a non-amino acid component.

  • Example of conjugated protein: hemoglobin (4 polypeptide chains + Fe/heme group)

What elements do nucleic acids contain

CHONP

Describe the structure of DNA

Key terms: nucleotide, deoxyribose sugar, phosphate group, nitrogenous base, sugar phosphate backbone, hydrogen bond, covalent bond, double stranded, helix, antiparallel

Compare and contrast the structure and function of DNA and RNA

Discuss the capacity of DNA to store information

• Any order of bases

• Any length 

• 4^n = # of possibilities

Explain why complementary base pairing is important for replication and protein synthesis

DNA REP 

-DNA replication occurs before cell division.

 -DNA strands serves as a template for the creation of a new strand 

- In this way, replication builds two identical DNA molecules, each with one original and one new strand.

Transcription 

-Transcription is the synthesis of RNA using a DNA template.

-One gene -> one RNA

-way to transfer the information stored in DNA in the nucleus to the ribosome. 

Translation 

Translation is the synthesis of a polypeptide from mRNA on the ribosome.

Base pairing of mRNA with tRNA leads to the formation of a polypeptide chain.

How is the genetic code evidence of universal common ancestor

• Genetic code = universal

• All protein are coded for in the same way

Explain directionality of nucleic acids and what is the implications of 5’ to 3’ directionality of DNA and RNA

Directionality of phosphate-sugar backbone

When nucleotides join together to make nucleic acid polymers. One part of the nucleotide is left exposed at each end.

The ends of the backbone are identified as 5’ and 3’. 

• 5’ end with a phosphate

• 3’ end with a pentose.

DNA is antiparallel

The two different strands of the DNA double helix run in opposite directions. At each end of the double helix, one strand is 5' and the other is 3'. 

Implications

The 5’ and 3’ directionality of DNA and RNA affect the way enzymes can bind to and function when bound to the nucleic acids.

• DNA polymerase during DNA replication

• RNA polymerase during transcription

• Ribosome during translation

Nucleic acids are always synthesized in a 5’ to 3’ direction.

Which nitrogenous bases are purines and which are pyrimidines

Explain the nature of purine to pyrimidine bonding

In the DNA double helix , a purine always forms a complementary pair with a pyrimidine by formation of hydrogen bonds. This hydrogen bonding imparts great stability to the DNA double helix.

• Adenine bonds to thymine by two hydrogen bonds

• Cytosine bonds to guanine by three hydrogen bonds

When a pyrimidine is paired with a purine, the width dimension of both pairs is identical. This means that the DNA sugar-phosphate backbones have a consistent diameter throughout the entire molecule.

Explain the structure of a nucleosome

The basic structural unit of DNA packaging is the nucleosome. 

• DNA coiled around a core of eight proteins → These proteins are called histones

• Histones are a family of small, positively charged proteins. 

• phosphate groups in nucleotides=DNA is negatively charged.  

• electromagnetic attraction. 

Hershey Chase Experiment

1. What was the purpose

2. What were the 4 technologies used during this experiment

3. Outline the key steps taken in the experiment

4. What was the conclusion of the experiment

1. To determine whether protein or DNA holds the genetic material

2. Bacteriophage, radioisotopes (P)(S), blender, centrifuge

3. 

4. Protein is not genetic material ( Isotope stayed w/ phage and did not enter bacteria) → this mean DNA going from the phage in to the bacteria means that DNA is genetic material

Chargaff experiment

1. What type of data did chargaff collect

2. What conclusions did he draw from this

1. How many bases were in certain organisms (used chromatography to separate bases)

2.  

   • The compositions of A,T,C,G bases varies from one species to another

   • % of G and C are roughly equal

   • % of A and 7 are roughly equal

What elements do carbohydrates contain

CHO

Outline the function of carbohydrates

Energy

• Immediate energy source of cells 

• Energy storage (short and long term)

Structure

• Structural role 

• ex. Cellulose makes cell wall in plants

• Ex. components of cell membrane: cell recognition and signaling

Explain how the structure of monosaccharides give rise to their properties

Form	Function
Ring structure- pentose or hexose	Chemical stability
Have several polar -OH groups	Solubility → easy to transport in blood or sap, soluble in water do to h bonding

Explain the energy properties of monosaccharides

1. Contains electrons and H atoms → have oxidative power

2. When exposed to O2 and energy input, the bonds will break, this creates loss of electrons and H atoms release energy

3. This energy is captured by ATP in cellular respiration

State 3 examples of disaccharides and their monosaccharide components

What are polysaccharides and how are they formed

• Result of condensation of 100s or 1000s of glucose molecules

• Different levels of branching and coiling

• Insoluble in water due to their large size

Compare and contrast the function of three types of polysaccharides

Explain why cellulose is not branch

• Cellulose is made of beta glucose

• Has an alternating orientation 

• Straight chain no branching

• Grouped in bundles → cross linked with H bonds

• Cellulose is made of beta glucose

• Has an alternating orientation 

• Straight chain no branching

• Grouped in bundles → cross linked with H bonds

• Carbohydrate chains attached to proteins and embedded in cell membrane 

• Play role in cell-cell recognition and signaling

Eg. antigens (ABO blood types)

Eg. receptors for hormones or other signaling molecules

Lipids are important for:

• Energy storage

• Buoyancy

• Thermal regulation

• Cell membranes 

• Protection of organs → shock absorption

What elements do lipids contain

CHOP

Differentiate between the 3 main types of fats

Triglyceride

• Glycerol + 3 fatty acid chains

• Animal fat and plant oils

Phospholipid

• Glycerol, phosphate group, 2 fatty acid chains

• Main component in plasma membrane 

Steroid

• Four fused ring structure

• - various functions

• Cholesterol- cell membrane

• Estrogen, progesterone, testosterone (hormones)

What is adipose tissue? Explain the function of triglycerides in adipose tissue

• Lipid storage cells in animal tissue

• Lipids are stored as triglycerides 

• Provides insulation, shock absorption

• Excess sugar is converted into fat for long-term energy storage.

• Insulation and buoyancy supports animals in arctic habitats.

Compare and contrast lipids and carbohydrate in terms of energy storage

Carbs	Lipids
Short term energy	Long term energy
Stored as glycogen in liver	Stored in adipose tissue as triglycerides
More easily digested = energy released faster	More slowly digested
Soluble in H20	Insoluble in H2O
17 kj/g	X2 the amount of energy (37 kj/g)

Explain the synthesis of triglycerides by condensation reaction

• When fatty acid forms bond with OH group on glycerol, 3 water molecules is removed

• Condensation reaction
  

Outline the difference between Saturated, monounsaturated and polyunsaturated fatty acids

Saturated	Monounsaturated	Polysaturated
-Straight chain -animal and plant sources No double bonds	-Bent chain → 1 double bond - plant oils	-Curved bent shape - 2+ double bonds -plant and fish oil

How do different types of fatty acids compare to each other in terms of structure and function

	# of double bonds	Melting point	Source	Function
Saturated	0	30-70 c	Animal fats	Insulation and cushioning in warm blooded animals
Monounsaturated	2	4 c (lowest)	Plant based oils	Energy storage, water barriers
Polyunsaturated	2+	-5-50c	Plant and fish oils	Energy storage, membrane fluidity

Why are saturated fats solid at room temperature? Why are unsaturated fats liquid at room temperature.

• Saturated fats back together more closely → solid at room temp ex. butter

• Unsaturated fats have more space between them → liquid at room temp ex. oil

Explain the synthesis of phospholipids by condensation reaction

•  When fatty acid and phosphate group bond with OH group on glycerol, 3 water molecules are removed 

• 

Explain how phospholipids form bilayers in water

• Hydrophobic tails orient toward middle away from water

• Hydrophilic heads on the outside in contact w/ water

• Micelles join together to form stable bilayers

Outline the structure and function of steroids

• 4 ring structure

• Non-polar

• Dissolve in membrane easily → helps with transport

• different t functions:

• Cholesterol- cell membrane and fluidity

• Testosterone, estrogen- sex hormones