SCIENCE FINALS 🧬🧫

1. Matter on Earth is either solid, liquid, gas or plasma.
2. Earth's 4 spheres "store" matter
• Atmosphere
• Hydrosphere
• " Biosphere
• Geosphere

ecosystems include
• Biotic and Abiotic factorsBiotic: living things such as plants/animals, fungi, bacteria
• Abiotic: nonliving such as soil, water, temp, and light

• A community: an interacting group of various species in the same geographical area at the same time.
• Example: Forest of trees contains birds, insects, snakes that all live together

• A population: a group of organisms from the same species living together in the same geographical area at the same time.
• Example: squirrels, grove of oak trees, rattlesnakes, bark beetles.

• 2 types of growth:
• Exponential
• Logistic
*Be able to identify each graph and explain what it represents

Exponential Growth: population size continues to increase indefinitely
Logistic Growth: population size reaches a
"maximum" and stays relatively stable

Maximum population size of a species that the environment can sustain indefinitely, given the available food, habitat, water, and other necessary resources

Energy
• 3 Main Forms
⁃ Light
⁃ Heat
⁃ Chemical
⁃ All living things use chemical energy to maintain homeostasis

Adenine Triphosphate (ATP)
• Form of energy
• Powers chemical reactions in your cell

How does CO, get into the plant?
Stomata (Stoma ~ singular form)
• Structure on leavesControls the flow of gases into and out of the plant.Opens to let CO, in; O, and water vapor out.
• Evapotranspiration: water vapor exiting a plant cell through the stomata
Controlled by guard cells
Controls the RATE OF PHOTOSYNTHESIS

Photosynthesis- Light dependent reaction
• Occurs in the thylakoid
• Energy is transferred to electrons in chlorophyll pigment (or other pigments.)
• This activates a system that splits H, into hydrogen and oxygen
• oxygen is released as waste or a by-product.
• "Excited" electrons move through the electron transport chain and produce molecules of ATP and NADPH.

Photosynthesis- Calvin Cycle aka Light
Independent Reaction
1. Plant absorbs CO, from the surroundings. (through the stomata)
2. In the stroma, CO2
is "fixed"
using energy from ATP and
NADPH to form a simple
3 carbon sugar.
3. Two of these simple sugars combine to form glucose.
4. Cycle must happen at least 2 times

The Equation for Photosynthesis
6C02 + 6H,0 Light ~ C6H206 + 602
• Reactants:
⁃ CO (carbon dioxide) + H,0 (water) AND LIGHT
• Products:
⁃ CHO (glucose) + 0, (oxygen)
• Light energy is used to convert water and carbon dioxide to high energy sugars and oxygen.

Factors affecting the rate of photosynthesis
1. Temperature: Enzymes function between 0° and 35°C
2. Light Intensity
3. CO, concentration
4. Water: must be available

Where dose cellular respiration occur
Starts in the cytoplasm
Ends in the mitochondria (vocab term) the "powerhouse" of the cell!

Two types of cellular respiration
Aerobic -- requires oxygen
Anaerobic -- does NOT require oxygen (less efficient)
3 stages of cellular respiration
1. Glycolysis: break down of sugar
Kreb's Cycle: produces CO2
3. Electron Transport Chain requires 0, AND produces a lot of atp (32)

The equation for cellular respiration
CH + 602 → 6C0, + 6H,0 + 38 ATP
Reactants:
Glucose
Oxygen
Products:
Carbon Dioxide
Water
ATP

Fermentation Types

Alcoholic Fermentation
Used by Yeast o Yields CO, and ethanol
Used to produce bread and alcohols
Lactic Acid Fermentation
Used by some bacteria
Yields lactic acid
Muscle cells use this to make ATP in the absence of oxygen

Earth's History and the cycling of matter and energy
• Earth's age is 4.5 billion years
• Evidence:
• Meteorites
• Moon rocks
• Earth's oldest minerals.
• Evidence collected throughRadiometric Dating.

Radiometric Dating
• process of determining age of rocks from the decay of their radioactive elements

What was early Earth like?
Evolving Atmosphere:
• Earliest: hydrogen and helium (too light, escaped into space)
• Early: mostly CO, with some water vapor. ammonia, and methane.
• Current: 78% Nitrogen, 21% Oxygen, and less than 1% everything else (including CO,).

How did the atmosphere change?
• Early Earth was HOT!!Early Earth had lots of volcanic outgassingEarth slowly cooled, water vapor in atmosphere condensed.
• . Torrential rains may have filled the oceansComets (made of minerals and water) may have also contributed to formation of oceans as They hit early Earth.

Maintaining Homeostasis
2 Feedback Systems
• Negative Feedback Loops
• CounterbalancingStabilizingMost body systems rely on negative feedback to achieve homeostasis.
• Positive Feedback Loops
• Reinforcing: escalates or amplifies responseUnstableLess commonCan be dangerous or even cause death if prolonged.

What Is Happening Inside the Cell to Maintain Homeostasis
Each of our cells need to move nutrients inside our cells to produce
ATP and build the biomolecules needed for life.
Our cells also need to move waste out of the cell. (ex. CO,, lactic acid, creatinine)
Our cells need to maintain an internal balance of pH and chemicals inside the cytoplasm to preserve all cellular functions.
So, how do they do this?

Diffusion (Passive Transport)
Simple
Diffusion
Facilitated
Diffusion by
Carriers
Facilitated
Diffusion by Channels
Movement from high to low concentration across the cell membrane that does not require energy
Ex. osmosis
Carrier proteins allow large lipid insoluble molecules to cross membrane
Channel proteins (hydrophilic pores) in membrane allow inorganic ions to pass through membrane

Movement of a substance across the cell membrane against the concentration gradient - against diffusion i.e. from low to high concentration
REQUIRES ENERGY usually in the form of ATP

Cell Division
• In multicellular organisms:
• Cell division = growth in overall size of the organism
• Enables an organism to repair and maintain its body
• In unicellular organisms (like bacteria):Cell division is a form of asexual reproduction.

• Larger cells have trouble moving waste out and needed materials in
• As cells get bigger, their volume increases FASTER than their surface area
• Before a cell grows too large, it divides into two new"daughter" cells.
• Reduces cell volume
• Results in an increased ratio of surface area to volume, for each daughter cell.
• Daughter cells DNA isIDENTICAL to parent cell
Eukaryotic Cell Cycle
• The life cycle of a cell from one division to the next
• The eukaryotic cell cycle consists of two major phases:
• Interphase is the time between cell divisions (growth period)Includes G1, S, and G2 phases
• The M phase is the period of cell division.
G1 phase
• Cell grows physically larger
• Organelles are copied
• Molecular building blocks (monomers) needed to build nucleic acid and proteins in later steps are gathered
• ATP is produced to have the energy needed for later steps
S phase
cell synthesizes a compete copy of its DNA
G2 phase
Cell grows more
Cell makes proteins
Cell begins to reorganize its contents to prepare for cell division (mitosis)
M Phase
• 2 Phases
• Mitosis: division of cell nucleus
• Cytokinesis: division of cytoplasm and organelles
How dna is organized
• Chromosomes
• Carry genetic information that is passed from one generation to the next Makes it easier for cells to copy DNA anddistribute equally into daughter cells.

Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
A period of cell growth, DNA replication, and preparation for cell division
Chromosomes condense, nuclear membrane dissolves,and spindle fibers begin to form
Chromosomes line up in the middle of the cell, spindle fibers attach to centromeres at opposite poles of the cell
Spindle fibers pull sister chromatids apart, bringing them to opposite sides of the cell
Nuclear membrane reforms around each set of chromosomes, the cell membrane begins to push inwards
Two identical daughter cells are produced when the cell membrane separates the two cells completely

Copy - Before a cell divides, it must make a complete copy of every one of its genes (during S phase)
Store - DNA stores information for genes that control patterns of development
Transmit - Pass the genetic
information from one cell to daughter cells
Nucleotides
Monomer made up of:
Nitrogenous base
Deoxyribose sugar
Phosphate group
Nucleic Acids
Long molecules
(polymeres) found in the cell's nucleus
Subunits (monomers): nucleotides
DNA has 4 nitrogenous bases
According to Chargaff's Rule:
The percentages of
adenine [A] = thymine [T]
The percentage of
guanine [G] = cytosine [C]
DNA Replication
Replication: Occurs during S phase of cell cycle
• DNA is duplicated BEFORE cell division
Each strand serves as a template (model) for the new strand.
The Replication Process
• Both strands of the double helix separate, or "unzip,"
• Forms replication forks (occurs at multiple locations)
• New bases added following base pairing rules (A=Tand C=G)
Replication Results
Each DNA molecule resulting from replication has one original strand and one new strand.
That's why it's called semi-conservative
Mutations
• Inheritable changes in genetic information
• Caused by:
• Random Errors in replication
• StressPhysical Mutagens (x - ray, UV light)
• Chemical Mutagens (pesticides, tobacco)

Effects of Mutations
• NoneChange has no effect on the AA inserted
• HarmfulDisrupts normal cell function
• Sickle Cell Anemia
• Hemophilia o Cancer
• BeneficialChange increases variation in the species and improves chance of survival in changing environmental conditionsPesticide resistant mosquitoes
• Polyploidy plants

How Enzymes Play an Important Role
• Unwind DNA strands
• Unzip DNA strands
• Add nucleotides
• Proofread copied DNA
• Join copied fragments of DNA together
• Lengthen chromosomes to prevent loss of DNA

Central Dogma
DNA to Protein
DNA: book of instructions that tells which
proteins to make
The path from genes to proteins has two steps:
1. Transcription-copying the DNA codes to make RNA
2. Translation-RNA codes used to make proteins

Proteins
• The body produces many different proteins.
• Proteins function best within specific conditions.
• Outside those conditions the chemical bonds between the amino acids making up the proteins may break, causing the protein to lose its structure and function.
• Denaturation is when a protein loses its function.
• The body produces many different proteins.
• Proteins function best within specific conditions.
• Outside those conditions the chemical bonds between the amino acids making up the proteins may break, causing the protein to lose its structure and function.
• Denaturation is when a protein loses its function.

Protein Functions
• DNA provides instructions that code for the formation of protein
• Proteins carry out most of a cell's work.
• Cells must produce many different types of proteins to carry ou the different functions.

Structure of RNA
Composed of 3 parts:
1. Phosphate group
2.5 carbon sugar
3. Nitrogenous base (Adenine, Cytosine, Guanine, and Uracil) NOT Thymine!!

3 forms of RNA
mRNA
(messenger)
carries copies of the instructions for protein synthesis from the nucleus to the cytoplasm
tRNA (transfer)
transfers the amino acids to the ribosomes in the order specified by the mRNA
rRNA (ribosomal) is part of the structure of ribosomes (where proteins are made)

Transcription
• DNA is read and a complementary strand of RNA is produced
• Occurs in nucleus
Translation = Protien Synthesis
mRNA (from transcription) is then translated by the ribosome.
*occurs at the ribosome in cytoplasm
tRNA brings the appropriate amino acids that are
sequenced to create the protein.

The Genetic Code
• 4 letters: A, U, G, and C
• 64 possible 3 letter combinations from 4 letters (4 × 4 x 4 = 64)
• Codon: 3 letter code found in mRNA
• one AA per codon
• some AA have multiple codons
• Anticodon: 3 letter code found in tRNA that carriesAA and is the complement of a codon (on mRNA)
memorize the steps of mitosis in there order as a whole