bio

08/23/2024 - Organization of Biology

Elements:

An element is a substance that cannot be broken down by ordinary chemical reactions.

A group of all the same atoms that is difficult to break

Atoms:

An atom is the smallest unit of matter that is unique to a particular element

Electrons are negatively charged particles. The electrons interact with other atoms (form bonds) and capture and release energy

Neutrons have no charge

Protons have a positive charge

Atoms are usually electrically neutral because they have an equal number of positive protons and negative electrons.

When you lose electrons, you get a positive charge, when you gain electrons you gain a negative charge.

Proton number doesn’t change

Ions:

Ions are atoms that are electrically charged because they have gained or lost electrons

Cation is positive

Anion is negative

Chemical Bonds:

A chemical bond is an attraction between atoms, ions or molecules that enables the formation of chemical compounds. Types:

Covalent

Polar

Non-Polar

Ionic

Hydrogen

Covalent bonds holds atoms together when they share one or more pair of electrons between atoms

Means “Sharing electrons”

Nonpolar Covalent:

Atoms share electrons equally

Polar Covalent:

Atoms share electrons unequally

Ionic bonds are attractions between positive and negative ions.

Hydrogen bonds are attractions between polar molecules

The attraction between slightly positive and slightly negative regions of two different polar molecules is called a hydrogen bond. H-Bond are represented with a dotted line

Water:

Water is important because

Most organisms have high water content (75% - 95%).

Many organisms live in water

Most chemical reactions of life take place in water

Structure of water consists of 2 hydrogen atoms and 1 oxygen atom, hence H2O.

Electrons are being shared between the oxygen and hydrogen atoms, so it’s a covalent bond.

The Hydrogen atom is weakly positive, while the

Water molecules are polar

Because the oxygen atom has more protons, it attracts the shared electrons more of the time, creating an equal distribution of charge

Intermolecular Hydrogen bonds form between different water molecules

Partly positive hydrogen bonds atoms of one water molecule are attracted to the partially negative oxygen of a different water molecule

Each water molecule can form H-bonds with up to 4 other water molecules.

The bonds in the water molecules are covalent, but the bonds between the water molecules are H-Bonds.

Scientific Theories:

A scientific theory is not a theory in the usual sense as a guess, but is supported by facts and multiple explanations. They are called theories because they can’t be proved 100%, but they have been observed

08/27/2024 - Water Structure and Bonding

1. Polarity:

Water has interesting properties because it is a polar molecule

Like a battery, it has a positive and a negative end

Water is polar because the shared electrons are attracted to the oxygen more strongly than by the hydrogen atoms causing Dipoles: Slight + or - charges

Because of Water’s two hydrogen atoms, it has two positive poles. This is where “dipoles” comes from.

The positive end of one water molecule attracts the negative end of another water molecule until all the water molecules are connected

2. Cohesion:

When water molecules stick to other water molecules it’s an effect called Cohesion

Hydrogen bonds are what causes liquid water to stick together.

Cohesion creates Surface Tension

Cohesion at the surface of water makes it behave as if it were coated with an invisible skin. ← The “Skin” is the Surface Tension

Surface tension allows for water to form droplets of rain helping to complete the water cycle

Organisms can use surface tension to “walk” on water to escape predators or find prey

Think water striders.

3. Adhesion:

When water sticks to other objects, it’s called Adhesion

Adhesion is caused by hydrogen bonds

Objects attracted to water are called “Hydrophilic”

Means “Water-Loving”

Objects that repel water are called “Hydrophobic”

Means “Water-Fearing”

4. Capillary Action:

The ability of a liquid to rise in a narrow tube or to be drawn into small openings Passively is called Capillary Action

Caused by Cohesion and Adhesion.

Purely passive, requires no energy.

Plants rely on this feature of water to move water through small tubes (veins) from the root to the leaves.

The evaporation of water from a leaf (Transpiration) exerts a pulling force on water in the veins and the cohesive force pulls the water up against the force of gravity.

5. Universal Solvent:

Water is often known as the Universal Solvent, because so many substances dissolve in it

Other polar molecules like salt and sugar dissolve easily in water. Hydrophilic.

Oil is nonpolar, and doesn’t dissolve in water. Hydrophobic

By dissolving salts and sugars, water allows living things to transport nutrients more easily through their bodies.

Water also provides a medium for the chemicals of life to come together and complete the chemical reactions necessary for life.

Hydrophobic Interactions:

Hydrophobic substances are repelled by the water because they are not polar - think lipids

Oil and Water don’t mix

Important: This allows for the creation of a bilayer membrane in all cells that doesn’t dissolve in its watery environment.

6. High Heat Capacity:

Water requires more heat to increase its temperature because the hydrogen bonds must first be broken.

The effects of hydrogen bonding give water a high specific heat

“Specific heat” is the measure of heat it takes to raise the tempe of 1 gram by 1 degree K

Due to H-Bonds

H2O resists changes in temperature

Takes a lot to heat it up

Takes a lot to cool it down

In this way the oceans moderate temperatures on Earth, and in your body. If our bodies did not have so much water, we would constantly be charred by the sun

When water evaporates, it has absorbed a lot of energy, so it takes energy with it

That’s why sweating cools mammals and helps them maintain homeostasis.

Organisms living in water don’t experience wide changes in temperature

Water regulates temperatures on land by absorbing heat and cooling air

7. Water Expands with it Freezes:

When most liquids get cold, their molecules move closer together and become a denser solid.

The hydrogen bonds in water cause the molecules to move apart when it becomes solid, increasing the volume and lowering its density allowing it to float.

Macromolecule Notes - 08/29/2024

Standard Deviation:

Used to determine how much variation there is between sample numbers and mean

It’s a measure of precision

Getting a high standard deviation means there is a problem with maintaining precision throughout the trials.

It’s a measure of consistency, really.

Even if the standard deviation is low, the trial could be wrong consistently

Accuracy:

Measure of how close a value is to the predicted value (true value)

Precision:

Measure of how close a value is to other values, or sample (Ex. Drops on the penny)

Macromolecules:

Macromolecules

Large molecules in living cells

Macro = big

Macromolecules are made by joining together thousands of smaller molecules (think Legos)

Monomers:

The small molecules are called monomers

Monomers join together to make polymers (macromolecules).

Organic vs. Inorganic

Organic compounds: Compounds that contain Carbon with hydrogen attached

Ex: Carbs, Lipids, Protein, and Nucleic Acids

Inorganic Compounds: No Carbon Hydrogen bonds

Ex: H2O, salt (NaCl), O2, vitamins, CO2, and minerals.

Organic Molecules, in living things, contain Carbon. Carbon always forms four covalent bonds. For example in methane, CH4

Carbon can also bond with other carbon, allowing it to form more complex molecules.

Carbohydrates (sugars):

Made of C H O in a ratio of 1:2:1

Made of monomers called monosaccharides

Glucose (sugar), and fructose are monosaccharides: Made of 1 monomer

Disaccharides: Have 2 monomers

Polysaccharides: Have many monomers.

Examples of polysaccharides:

Plants store their extra glucose in the form of starch

In plants, glucose molecules join together to make cellulose. The cell wall of plant cells is made of cellulose.

In animals, glucose molecules join together to make glycogen, which is stored for energy in the muscles and liver.

Carbohydrates are the main source of quick energy.

Functions of Carbohydrates Summarized:

Plants make glucose (sugar)

Glucose is stored as starch in plants (potatoes, wheat, corn) and as glycogen in animals

The cell wall is made of cellulose.

If a word ends in “OSE”, that means it probably is a sugar (carbohydrate).

Ex: Glucose, fructose, cellulose, lactose, galactose, maltose, etc.

Macromolecule Notes 2- 09/04/2024

Lipids:

Made of Carbon, Hydrogen, and Oxygen: C H O

Mostly made of C and H, very little O

Monomer = Glycerol/Fatty Acids.

The monomer is made by joining a glycerol molecule and 1 or more fatty acids.

Ex: Phospholipids have two main chains, triglyceride has 3, and steroids are weird.

Saturated Fats have only single bonds, and has all the possible hydrogens.

It’s called “Saturated” because it has all the needed hydrogen atoms

Solid at room temperature

Unsaturated Fats can have double or triple bonds between carbons. They are also bent unlike saturated fats.

Liquid at room temperature.

Unsaturated fat is known as healthy fat.

Fish are good to eat to get unsaturated fat because of their cold environment or something.

Salmon, Tuna, Mackaral?

Steroids

Many hormones are steroids but not all of them are

Steroid hormones derived from cholesterol

If you see the four ring structure, then you’re dealing with cholesterol.

It looks like 3 hexagons and a pentagon.

Functions of the Lipids:

Lipids store energy (fat)

Lipids are good temperature insulators (body fat)

Lipids make cell membranes

Lipids make waterproof coverings (skin): Waxes, oils (liquids), fats (solids)/

Hormones are sometimes made of lipids