Lecture 1/2: Into to the cell

Cell Theory has how many components

3

Part 1 of cell theory

All living organisms are made up of one or more cells.

Part 2 of cell theory

The cell is the basic unit of life.

Part 3 of cell theory

All cells arise from pre-existing cells.

Schwann

postulated the first 2 parts of the cell theory

Virchow

expanded on cell theory by stating that all cells arise from pre-existing cells.

How could humans be descendants from stars

This idea is based on the concept that the elements that make up human bodies were formed in stars and released into space when those stars exploded as supernovae.
Hydrogen and helium fusion

How can life be categorized as the flow of energy using thermodynamics

2nd law of thermodynamics says entropy (disorder) always increases since things always decay and break down into simpler components. But cells are a closed system and do not follow this because they input energy to build things and become more organized. So life is influx of energy.

Why do people say life originates from nonliving cells

This statement reflects the theory of abiogenesis, which posits that life arose from simple organic compounds through chemical processes, eventually leading to the formation of living cells.

Basic chemical elements in life

C, H, O, and N

What 2 reasons make carbon the best atom to be the backbone of life

1. Can make stable covalent bonds
2. Can generate diverse structures

Why can carbon generate diverse asymmetrical structures

Because 1 carbon can form up to 4 bonds

Alcohol

Carbonyl

C=O bond within aldehydes and ketone and esters

Aldehyde

Ketone

Carboxylic acid

Esters

Amines

Amides

Sulfhydryl group

Phosphate groups

Stereoisomer

Compounds with the same molecular formula but different spatial arrangements of atoms.
Mirror images of each other

2nd Law of thermodynamics

More disorder overtime in a closed system, energy transformations increase entropy.

Entropy (S)

Degree of disorder

Macromolecules can be considered

Carriers of information to be formed and read in a cell

Delta G

The change in free energy of a system, indicating the amount of work that can be performed by a thermodynamic system at constant temperature and pressure.

how does a cell generate macromolecules

First food must be broken down to generate energy then this energy is stored and used for cellular processes like building macromolecules such as proteins, nucleic acids, and polysaccharides.

Most Widely Used Activated
Carrier Molecule

ATP (Adenosine triphosphate)

ATP

What type of bonds connect the 3 phosphate groups in ATP

Phosphoanhydride bonds.

ATP is metabolized to

ADP

The reaction to break down ATP to ADP is considered spontaneous, what does this mean

It means that the reaction occurs naturally without the need for external energy input, as it leads to a more stable state.
Negative delta G

Polar side chain of polypeptide

On the outside of the molecule to hydrogen bond with water in environment

Nonpolar side chain of polypeptide chains

Hydrophobic so it goes to the core region of the folded polypeptide

Non-covalent interaction function in life

crucial for transforming information into functionality

Electrostatic interactions

are attractive or repulsive forces between charged particles, playing a key role in stabilizing protein structures and interactions.

Hydrogen bonds

are weak attractions between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom, essential for maintaining the structure of proteins and nucleic acids.

Hydrophobic forces

are interactions that occur between nonpolar molecules in aqueous environments, driving the folding of proteins and the formation of cellular membranes. Due to repulsion

Van der waals interactions

are weak attractions between molecules or parts of molecules that result from transient local partial charges, significant in molecular recognition and stability.

Protein folding uses what types of interactions

H bonds

Ionic

Van der waals/ hydrophobic

Disulfide bond

Effect of water on electrostatic interactions and hydrogen bonding

Weaker because charged groups are shielded (salt dissolving)

How are peptide bonds formed

Condensation reaction between Amino group and carboxyl group

Directionality of polypeptides

always read from n to c terminus (left to right)