Biology Final Exam Study Guide

Describe seven fundamental properties of life and how they make living things unique

1. Cells (viruses have no cells not alive)
2. Energy use/metabolism (chemical reactions inside body)
3. Interact with the environment (ex: response to heat)
4. Maintaining homeostasis (Same standing, things that need to be regulated like body heat.)
5. Growth and development (Something that is alive has to grow and develop in some way)
6. Contain genetic material (Genetic code (DNA RNA) Certain sequences (AGCT) stand for the same
protein/enzyme for all organisms)
7. Populations evolve towards higher fitness (Biological fitness is the ability to produce offspring)

Biological evolution

A heritable change in a population of organisms from one generation to the next
- having the ability to reproduce fertile offspring

Mutation

Change in DNA sequence that affects genetic information

Natural selection

The process that eliminates those individuals that are less likely to survive and reproduce in a
particular environment, while allowing other individuals with traits that confer greater reproductive
success to increase in numbers.

3 domains of life

Bacteria, Archea, and Eukarya

Bacteria: cells don’t have nucleus
Archea: cells don’t have nucleus
Eukarya: cells do have a nucleus

Hypothesis and its steps

Hypothesis: a testable prediction
1. Observations are made regarding natural phenomena.
2. These observations lead to a hypothesis that tries to explain the phenomena. A useful hypothesis is
one that is testable because it makes specific predictions.
3. Experimentation is conducted to determine if the predictions are correct.
4. The data from the experiment are analyzed.
5. The hypothesis is considered to be consistent with the data, or it is rejected.

Atoms & their make up

Atoms: smallest particle of matter (belonging to a certain element)
3 Subatomic Particles: protons, neutrons, electrons

Protons

A positively charged particle found in the nucleus of an atom

Neutrons

A neutral particle found in the nucleus of an atom

Electrons

A negatively charged particle found in the orbitals around an atomic nucleus

Electron shells

The region around an atom's nucleus where electrons reside; larger atoms have more electron shells than smaller atoms

Mass Number

The sum of the number of neutrons and protons in an atomic nucleus

Polar covalent bond

A covalent bond in which electrons are not shared equally. The shared electrons are pulled closer to
the more electronegative atom, making it slightly negative and the other atom slightly positive.
-hydrophilic

Non polar covalent bond

A strong bond formed between two atoms of similar electronegativities in which electrons are shared
between the atoms.
-hydrophobic

Ionic Bond

The bond that occurs when a cation binds to an anion (medium strength)

Hydrogen bond

Results from attraction between opposite partial charges (weak and short lived)

Bonds that occur between water molecules

Hydrogen bond: formed in liquid water as the hydrogen atoms of one water molecule are attracted towards the oxygen atom of a neighboring water molecule

Important functions of water

Participates in chemical reactions
Hydrolysis or dehydration
Provides force or support
Remove toxic waste components
Evaporative cooling/Heating of vaporization
Cohesion and adhesion

Solute

Substance that is dissolved

Solvent

Substance in which the solute dissolves

Solution

A liquid that’s contains one or more dissolved solutes

Hydrophobic

Water hating
Example: oils, fats, and greases

Hydrophilic

Water loving
Example: sugar, salts, starch, cellulose

Amphipathic

Having both a hydrophobic and hydrophilic region

Describe why ionic compounds and polar molecules dissolve in water and explain how this relates to the saying “like dissolves like.”

The ions are attracted to the water molecules, each of which carriers a polar charge. The compounds dissolve due to the strong attraction of ions and the water molecules.

Acid

A molecule that releases hydrogen ions (H+) in solution
Example: nitric acid, hydrochloric acid

Base

1. A molecule that lowers the H+ concentration when dissolved in water
2. A component of nucleotides that is a single or double ring of carbon and nitrogen atoms
Example: potassium, sodium

pH

A measure of how acidic or basic a solution is

Reactions that form and break down polymers

Hydrolysis reaction: a chemical reaction that uses water to break other molecules apart

Dehydration synthesis: a chemical reaction in which two molecules are bonded together with the removal of a water molecule

4 major macromolecules and their functions

Carbohydrates, lipids, proteins, and nucleic acids

Carbohydrates: broken down to glucose to be the main source of energy for the body

Lipids: chemical messengers, storage, and provision of energy

Protein: most of the work in cells, needed for structure, function and regulating body tissues and organs

Nucleic acids: store and transmit genetic information (DNA and RNA)

Explain why high temperature and pH affect protein shape

Destruction of the normal shape of the protein and affects the function

4 features all cells have

Plasma membrane, cytoplasm, ribosomes, DNA

Differences between prokaryotes and eukaryotes

Prokaryotes:
- no nucleus
- smaller
- are single-celled

Eukaryotes:
- has a nucleus
- are bigger
- have membrane-bounded organelles

Organelle

Specialized structure that does the important cellular functions with the eukaryotic cell

compartmentalization in eukaryotes

Use of a series of internal membranes

Differences between plant and animal cells

Plant cells:
- have chloroplasts
- have a cell wall
- have a large center vacuole
- shape is rectangular

Animal cells:
- no chloroplasts
- no cell wall
- small vacuole
- shape is odd/round

Endosymbiosis theory

Theory that the eukaryotic cell was made as a result of prokaryotes undergoing endosymbiosis
Evidence: chloroplast & mitochondria make energy for the cell

journey of a secreted/membrane bound protein

Rough ER -> Golgi -> secretory vesicles -> cell exterior

Selective permeability

The property of a plasma membrane that allows some substances to cross more easily than others

How polarity and size affects solutes going through easily

Small molecules pass more easily and nonpolar (hydrophobic) molecules pass more easily

Molecules with high and low permeability

High permeability:
O2, N2, CO2 (also very small uncharged nonpolar molecules)

Low permeability:
Ions, large charged polar molecules, and macromolecules (amino acids, atp, proteins)

Passive and active transport

Passive: requires no energy (movement from high to low concentration, moves with concentration gradient)

Active: needs energy (movement from low to high concentration, and moves against concentration difference)

Simple and facilitated diffusion

Simple: a diffusion that doesn’t involve a direct input of energy or assistance by carrier proteins

Facilitated: a diffusion that involves movement of specific molecules across cell membranes through carrier proteins and transport proteins

Explain how osmosis is an example of diffusion

This is because there is a movement of particles from a higher concentration region to a lower one

Hypertonic, hypotonic, and isotonic

… to be continued, wowowowowow

Differences between passive and active transport

Passive: doesn’t require energy

Active: does require energy

Primary active transport and secondary active transport

Primary active: direct use of energ to transport solute in or out of the cell against concentration gradient

Secondary active: usage of an already existing gradient of one molecule to pull a different molecule against its concentration gradient

5 major types of cell signaling

Direct intercellular signaling, contact-depending signaling, auto-crine signaling, Paracrine signaling, endocrine signaling

Direct intercellular signaling

Cell junctions allowing signaling molecules to pass from one cell to another

Contact depending signaling

Cells that need to make contact to pass signals

Autocrine signaling

Cells producing signaling molecules that bind to their own cell surface or a neighboring one of the same type (affects nearby cell and the originator)

Paracrine

Signal does that affect cell that’s producing the signal, but affects others in close proximity (affects nearby cell but not the originator)

Endocrine

Signals that travel long distance and last longer

3 steps of cell signaling

1. Receptor activation
2. Signal transduction
3. Cellular response

Explain why the absence of a receptor makes a cell unable to respond to a signal.

… to be continued

Describe why a drug that mimics the shape of a natural signal may alter normal signaling.

… to be continued

Energy

The ability to do work

Types of energy: heat, light, electricity, mechanical energy, and chemical energy

Exergonic and Endergonic

Exergonic: breaks things apart (spontaneous reaction) negative free energy change
ΔG

Explain how energy coupling is used to get an endergonic reaction to occur. Which molecule is often broken down to power an endergonic reaction?

…

Role of activation energy

activation energy is the energy that’s needed to start a reaction

Why cold temperatures aren’t ideal for reactions

There’s not enough heat to start the reaction and the enzyme doesn’t function properly to speed up a reaction

Explain how an enzyme increases the rate of a biochemical reaction

The enzyme reduces the activation energy needed for the reaction to occur

Explain why enzymes catalyze one specific chemical reaction

Enzyme specificity is the concept that each enzyme catalyzes with only one kind of reaction.
- the enzyme only bonds with one substrate due to the shape of an active site

Predict how high temperature and pH can affect enzyme shape and enzyme activity

When the ideal temperature is too high, the protein will denature and wont be able to function and decreases the rate of reaction

Summary equation for cellular respiration

C6H12O6 + 6O2 → 6CO2 + 6H2O

Describe the energy transformations during cellular respiration

….

Explain how the Electron Transport Chain gets energy to pump Hydrogen ions against the gradient

NADH and FADH2 donate electrons to the electron transport chain

Describe how ATP Synthase uses the Hydrogen gradient to get energy to make ATP (endergnic).

With the process of chemiosmosis which uses energy in the form of H+ gradient across a membrane to turn ADP to ATP

escribe what happens to cellular respiration if the final electron acceptor oxygen is not present

Oxygen is the final acceptor in the electron transport chain, and if oxygen isn’t there, ETC will not run and ATP wont be produced through chemiosmis and ATP synthase

Cellular respiration vs fermentation

Cellular respiration:
- oxygen is present
- uses the 4 stages (glycolysis, breakdown of pyruvate, citric acid cycle, oxidative phosphorylation)
- makes 34-38 ATP

Fermentation
- no oxygen
- uses only glycolysis
- makes only 2 ATP

Why will cells that are capable of fermentation preferentially carry out cellular respiration?

Cellular respiration is more productive for making energy

Heterotroph vs Autotroph

Hetero: an organism that can’t make its own food and eats organic molecules to survive (animals, fungi)

Autotroph: an organism that can make its own food (plants, algae)

Energy cycling in the biosphere

Energy enters the ecosystem from the sun and exists after the organism have taken as much as needed. Organism release energy back into the biosphere as heat.

First law of thermodynamics

Energy cannot be created or destroyed

How autotrophs like plants affect the CO2 levels in the environment

The more CO2 that’s being consumed, the lower the CO2 levels there will be

Summary equation for photosynthesis

C6H12O6 + 6O2 → 6CO2 + 6H2O
Carbon dioxide + water → glucose + oxygen

Why plants have to do photosynthesis and cellular respiration

They need to produce energy (ATP) and they can’t get this from another other source

Pigment

A molecule that can absorb light energy

2 things that happen when light hits pigments
And why they appear a certain color

2 things: Some wavelengths of light are absorbed, while others are reflected

Why they appear a certain color: the wavelengths of energy that pigments reflect are what color they appear to us

Most effective and less effective light for photosynthesis

Most effective: red, blue, orange

Least effective: green
(White light is most effective, because it has a wide variety of colored lights for pigments to use)

how ATP is made as electrons flow from PS II to PS I

…

energy transformations that occur during light reactions and Calvin cycle

…

Photosynthesis vs Cellular Respiration

Photosynthesis:
- energy storage (making chemical energy)
- endergonic reaction (building complex molecule)
- reactants: light energy + CO2 + H2O
- products: glucose + oxygen
- requires input on energy

Cellular respiration
- energy usage
- Exergonic reaction (breaking down complex molecule)
- reactants: glucose + oxygen
- products: CO2 + H2O + Energy
- releases energy

4 criteria for genetic material

1. To contain information to make an individual
2. To pass from parent to offspring
3. To be accurately copied
4. To account for known variation within and between species

5 levels of DNA structure

1. Nucleotide
2. Strands
3. Double Helix
4. Chromosome
5. Genome

Base-pairing rules

A—T pairing
- adenine and thymine
- contains 2 hydrogen bonds

C—G pairing
- cytosine and guanine
- contains 3 hydrogen bonds

Nucleotide

The most basic unit of DNA strutucre and is composed of a sugar, a phosphate, and a nitrogenous base
- sugar outline is 1’-5’
- phosphate attaches to 5’
- base attaches to 5’

Strands

A chain of nucleotides

Double helix

Double stranded complementary strands

Chromosome

DNA strands that are associated with proteins that can be compacted into chromosomes

Genome

The complete genetic material of an organism or species

DNA vs RNA structure, bases, and functions

DNA - stores genetic information for cell

RNA - codes for amino acid and acts as a messenger between amino acids and ribosomes

Gene expression process

Transcription: making an RNA copy of a gene

Translation: making a specific polypeptide on a ribosome

Gene expression in Eukaroytes and prokaryotes

Eukaryotes:
-Transcription in nucleus
-Translation in cytoplasm
- Extra step: mRNA processing before translation

Prokaryotes:
Both transcription and translation are coupled and occur during the cytoplasm, due to no nucleus being present

3 steps of RNA processing

1. 5’ cap: the 5’ end of a pre-mRNA molecule that’s modified by the addition of a cap of guanine nucleotide
2. Poly A Tail: 100-200 adenine nucleotides added to 3’ end
3. Splicing: the removal of introns and the reconstruction of exons in the pre-mRNA

3 base pairs

1. Substitution: substitutes a single base pair for another one
2. Addition: adding a base pair in the DNA sequence
3. Deletion: removing a base pair in the DNA sequence

Missense, nonsense, and silent mutations

Missense: change in a single amino acid in a polypeptide

Nonsense: change from a normal codon to stop/termination codon

Silent: no change in the amino acid sequence (because multiple codons code for the same amino acid)

Eukaryotic cell cycle stages

G1, S, G2, and M

G1 phase

The process of cells dividing due to the environment and certain signals
- cell growth typically occurs

S phase

DNA being replicated during cell cycle
- 46 chromosomes with 2 sister chromatids