AP Biology Semester 1 Final Review

Units 1-5

water's cohesion

the sticking together of water particles because of its polarity

water's polarity

• Unequal sharing of electrons and V- like shape

• The oxygen region has a partial negative charge.

• Each hydrogen has a partial positive charge

water's adhesion

When water molecules cling to to another substance or object other than itself

water's high specific heat capacity

it takes a lot of energy to raise its temperature due to the strong hydrogen bonds absorbing heat before molecules move faster. Therefore, water can store and release heat slowly

water: universal solvent supports reactions

its polar molecule structure allows it to dissolve many substances by surrounding their ions or polar parts

water's heat of vaporization

More than 5x the amount of energy needed to raise the temperature of water from 0° C to 100° C. Due to strong H bonds between its polar molecules.

water's heat of fusion

334 J/g. significantly higher than most other common substances due to its strong H bonds that require a large amount of energy to break

water's thermal conductivity

High thermal conductivity because its molecules are close and H bonds allow efficient energy transfer thru vibration and convection.

Carbon moves from the environment to organisms where it is used to build _.

carbohydrates, proteins, lipids, or nucleic acids. Used in storage compounds and cell formation

Nitrogen moves from the environment to organisms where it is used to build _.

proteins and nucleic acids

Phosphorous moves from the environment to organisms where it is used in _.

nucleic acids and certain lipids

In nucleic acids, where is biological information encoded?

sequences of nucleotide monomers

structural components of a nucleotide

a 5-carbon sugar (deoxyribose or ribose), a phosphate, and a nitrogen base (adenine, thymine, guanine, cytosine, or uracil)

primary structure of a protein

the amino acid sequence of the polypeptide chain

secondary structure of a protein

protein structure is formed by the folding and twisting of amino acid chain

tertiary structure of a protein

protein structure is formed when the twists and folds of the secondary structure fold again to from a larger 3D structure

quartenary structure of protein

the arrangement of multiple polypeptide chains (subunits) into a single functional protein complex. This level is not present t in all proteins. Held together with weak: hydrophobic interactions, H bonds, and ionic interactions

what determines the function of a protein?

the specific order of amino acids (shape/structure)

R group of an amino acid

Side chain that determines the structure and function of the amino acid, categorized by chemical properties (hydrophobic, hydrophilic, ionic)

hydrophobic

Having an aversion to water

hydrophillic

Attracted to water

ionic

transfer of electrons

lipids

nonpolar molecules that include fats, oils, and cholesterol

phospholipids

nonpolar regions with a polar region that interacts w/ polar molecules (water). nonpolar regions where differences in saturation determine structure and function of lipids

carbohydrates

composed of sugar monomers whose structures and bonding with ear other by dehydration synthesis determine the properties and functions of the molecules. glucose, starch, cellulose, chitin

dehydration synthesis

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.

direction nucleotides are added during DNA synthesis / direction of transcription

5' to 3'

Structure of proteins

an amino (NH2) end and a carboxyl (COOH) end, and a linear sequence of amino acids connected by the formation of peptide bonds by dehydration synthesis between the amino and carboxyl groups of adjacent monomers

what does a carboxyl group do

makes things acidic

the nature of bonding between carbohydrate subunits determines:

their orientation in the carb, which determines the carb's secondary structure

how does directionality influence the structure and function of nucleic acids?

dictates how they're built and read

how does directionality influence the structure and function of proteins?

specific amino acid sequences fold into unique 3D shapes driven by directional bonds and interactions, leading to the proteins specific role / function

how does directionality influence the structure and function of carbohydrates?

dictates their 3D shape, creating vastly different structures (linear vs branched) that serve distinct functions (cellulose's rigid fibers for structure vs starch's compact chains for energy storage)

selective permeability

A property of a plasma membrane that allows some substances to cross more easily than others. described by the fluid mosaic model.

what is the structural framework of cell membranes?

phospholipid molecules, embedded proteins, cholesterol, glycoproteins, and glycolipids

how are the phospholipids orientated in the cell membrane?

the hydrophilic phosphate regions are towards the environment, while the hydrophobic fatty acid regions fact each other within the interior of the membrane

What charge can embedded proteins be?

Both hydrophilic (w/ charged and polar side groups), or hydrophobic )w/ nonpolar side groups)

what molecules freely pass across the membrane?

small nonpolar molecules (N2)

how do hydrophilic substances move across the membrane

the large polar molecules and ions move through an embedded channel and transport proteins.

how does water move across membranes

aquaporins (channel proteins)

types of cell walls

Plants: cellulose; Fungi: chitin; Bacteria: peptidoglycan.

Passive Transport (Diffusion)

the movement of substances across a cell membrane without the use of energy by the cell

How is glucose transported through the membrane?

Facilitated diffusion using glucose transporter proteins move down its concentration gradient

How is Na+/k+ transported though the membrane?

Active transport by the sodium-potassium pump, a protein that uses energy from ATP to actively pump 3NA+ and 2 K+ ions into the cell against their concentration gradient to maintain cellular electrical balance and function

the environment is hypotonic to the cell

the environment has a lower concentration of solute than the cell. water will diffuse into the cell.

the environment is hypertonic to the cell

the environment has higher concentration of solute than inside the cell. water will diffuse out of the cell.

the environment is isotonic to the cell

equal concentration of solute in the environment and cell. water diffuses with no net movement (equally diffuses)

Active Transport

a process where free energy (often provided by ATP) is used by proteins embedded in the membrane to move molecules and/or ions across the membrane to establish and maintain concentration gradients

Exocytosis

internal vesicles fuse with the plasma membrane to secrete large macro molecules out of the cell

endocytosis

the cell takes in macromolecules and particulate matter by forming new vesicles derived form the plasma membrane

How do internal membranes facilitate cellular processes?

by minimizing competing interactions and increasing surface area where reactions can occur (efficiency)

What is the Endoplasmic reticulum? What does it do?

A vast network of membranes. Crucial for making, folding, modifying, and transporting proteins & lipids, acting as a central factory and transport system. Smooth and Rough versions.

Rough ER vs. Smooth ER

RER compartmentalizes the cell, serves as mechanical support, provides site-specific protein synthesis with membrane-bound ribosomes, and plays a role in intracellular transport, while the SER makes lipids

What is the Mitochondria? What does it do?

Organelles with a double membrane that allows compartmentalization within it. The outer membrane is smooth, and the inner is highly complex, forming folds called cristae, which contain enzymes important to ATP production. cristae also increase surface area for ATP prodction.

What are Chloroplasts? What do they do?

Double membrane organelles found in only plant cells and they capture the energy from sunlight and convert it to chemical energy to store food during photosynthesis

What is the Golgi Apparatus? What does it do?

Its a cell organelle made of flattened membrane sacs (cisternae) that does: synthesis and packing of materials (small molecules) for transport (in vesicles), and production of lysosomes

What is the nuclear envelope? What does it do?

Double membrane that surrounds the nucleus, separating its contents from the cytoplasm. acts as a crucial barrier and communication hub, regulating molecule transport via nuclear pores, organizing chromatin, providing structural support, and plays roles in division and signaling

What are ribosomes?

small, universal structures comprised of ribosomal RNA and protein, which interact to become the site of protein synthesis where the translation of genetic instructions yields polypeptides

What are lysosomes

membrane-enclosed sacs that contain hydrolytic enzymes (break compounds down using water), important to intracellular digestion, recycling organic materials, and apoptosis.

what is a vacoule

membrane-bound sac that plays roles in intracellular digestion and the release of cellular waste products.

what do plant vacuoles do

large. store of pigments or poisonous substances, cell growth, etc. allows for a large surface area to volume ration

what are chlorophylls

in chloroplasts, responsible for the green color of a plant and are the key light-trapping molecules in photosynthesis. several types, predominant form being chlorophyll A

What are thylakoids?

membrane bound structures in chloroplasts that house energy capturing reactions. are organized in stacks called grana.

What is the endosymbiotic theory?

Complex eukaryotic cells evolved from simpler prokaryotic cells when one engulfed another in a symbiotic relationship

What is quorum sensing?

use of chemical messengers by microbes to communicate with other nearby cells and to regulate specific pathways in response to population density

What do signal transduction pathways do?

convert signals received at a cell's surface into cellular responses

what does epinephrine do?

aka adrenaline: stimulates glycogen breakdown (fight or flight)

how do immune cells interact

cell-cell contact, antigen presenting cells (APCs), helper T-cells and killer T-ce;;s

Plasmodesmata

channels through cell walls that connect the cytoplasm of adjacent cells; allows material to be transported from cell to cell

short distance cell communication

A cell sends a message to another cell nearby: synaptic (neurotransmitters), plasmodesmata, quorum sensing, morphogens, paracrine (cell releases local regulators), etc.

endocrine signlaing

signals released by one type of cell can travel long distances to target cells of another cell type

how is the transduction of a signal initiated?

a receptor protein recognizes ligand (signal molecule) which causes it to change shape

G-protein linked receptors

ligands bind to a receptor which activates a G protein causing the release of a second messenger such as cyclic AMP

Ligand-gated ion channels

Receptors that open in response to ligand binding.

Receptor tyrosine kinases

A receptor protein spanning the plasma membrane, the cytoplasmic (intracellular) part of which can catalyze the transfer of a phosphate group from ATP to a tyrosine on another protein.

signal transduction

the process where a signal is converted to a cellular response

signal cascades

relay signals from receptors to cell targets, often amplifying the incoming signals

second messengers

A small, nonprotein, water-soluble molecule or ion, such as calcium ion or cyclic AMP, that relays a signal to a cell's interior in response to a signal received by a signal receptor protein.

explain the consequences of the first and second laws of thermodynamics for living systems.

1st- life needs constant energy input to build ordered structures, as energy isn't created but transformed. 2nd- this energy conversion isn't perfect; every transfer releases unusable heat, increasing disorder (entropy_ in the surroundings

How can life adhere to the rules of thermodynamics and accomplish grow, increase in order, decrease in entropy, and reproduction?

living organisms are open systems that constantly exchange energy and matter with their surroundings. They do this by causing a greater increase in entropy in their environment since the 2nd law states entropy of an isolated system increases. Growth= they use energy and matter to build structures and size which decreases entropy. Reproduction= organisms bypass the individual thermodynamic limit by producing. Increase in order / decrease in entropy= the energy input powers cellular functions that build and maintain ordered structures.

what is entropy?

measure of disorder

exergonic

Chemical reactions that release energy; cellular respiration

endergonic

A chemical reaction that requires the input of energy in order to proceed; photosynthesis

anabolic

A process in which large molecules are built from small molecules; muscle growth

catabolic

A process in which large molecules are broken down; glycolysis

chemoheterotrophic

an organism that uses organic molecules as a source of carbon and energy

Photoautotrophic

organism that uses energy from sunlight to convert carbon dioxide and water to carbon compounds

inputs and outputs of glycolysis

Inputs: ATP, glucose, NAD+
Outputs: More ATP, pyruvate (Acetyl CoA, lactate, or ethanol), NADH

inputs and outputs of alcohol fermentation

• INPUTS: 2 pyruvate, 2 NADH
• OUTPUTS: 2 alcohol, 2 CO2, 2 NAD+

inputs and outputs of lactic acid fermentation

-INPUTS: glucose, ADP, NAD+
-OUTPUTS: Lactic acid, ATP, NAD+

inputs and outputs of aerobic cellular respiration

Inputs: Glucose, oxygen, NAD+, FAD
Outputs: 30-36 ATP, 6CO2, 6H20

major processes of aerobic cellular respiration

Glycolysis, Citric Acid Cycle, pyruvate oxidation, and Electron Transport Chain

What is Glycolysis?

in the cytoplasm: glucose is converted into 2 pyruvate, 2 net ATP are made, and NAD+ -> NADH

What is pyruvate oxidation?

each pyruvate goes into the matrix and is converted into a two carbon molecule bound to Coenzyme A (acetyl CoA). CO2 is released and NADH is generated.

What is the Citric acid cycle?

in the matrix: Acetyl CoA combines with a four-carbon molecule and goes through a cycle of reactions, ultimately regenerating the four-carbon starting molecule. ATP, NADH, and NADH2 are produced, and CO2 is released.

What is the Electron Transport Chain in aerobic cellular respiration?

NADH and FADH2 deposit their electrons in the ETC. As electrons move down the chain, energy is released and used to pump protons out of the matrix, forming a gradient. Protons flow back into the matrix through the ATP synthase, making ATP. At the end of the ETC, oxygen accept electrons and takes up protons to form water.

inputs and outputs of light dependent reactions

Inputs; light, energy & water
Outputs; ATP, NADPH & oxygen

inputs and outputs of calvin cycle

Inputs: 3 CO2, 9 ATP, 6 NADPH
Outputs: 1 G3P, 9 ADP, 6 NADP+

what is the light dependent reaction in photosynthesis?

in the thylakoid membrane: light is used to drive the production of ATP and NADPH. Water provides the electrons needed and is converted to oxygen gas (waste)

what is the calvin cycle in photosynthesis?

in the stroma: The ATP and NADPH produced in the light reactions are used to incorporate carbon dioxide into a 3-carbon sugar.