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What property of water allows it to form hydrogen bonds?

The partially positive hydrogen of one water molecule and the partially negative oxygen of another.

What is cohesion in the context of water?

The tendency of water molecules to stick to each other.

What is the significance of water's high specific heat?

It resists temperature changes, helping to stabilize environments.

What are the monomers of carbohydrates?

Monosaccharides, such as glucose and fructose.

What is the primary function of lipids?

Long-term energy storage, membrane structure, signaling, and insulation.

What are the building blocks of proteins?

Amino acids.

What is the structure of DNA?

A double helix with two strands held by hydrogen bonds between complementary bases (A-T, G-C).

What process joins monomers into polymers?

Dehydration synthesis.

What is hydrolysis?

The process of breaking polymers into monomers by adding water.

What is the role of ribosomes?

Protein synthesis.

What is the function of the Golgi apparatus?

Modifies, packages, and ships proteins.

What does the fluid mosaic model describe?

The structure of the cell membrane, which includes a phospholipid bilayer with embedded proteins.

What is passive transport?

The movement of substances across a cell membrane without the use of energy.

What is the sodium-potassium pump?

An active transport mechanism that pumps 3 Na+ out and 2 K+ in using 1 ATP.

What is the difference between autotrophs and heterotrophs?

Autotrophs make their own food from inorganic sources, while heterotrophs obtain food by consuming other organisms.

What is ATP?

The universal energy currency of the cell.

How do enzymes function?

They speed up reactions by lowering activation energy and are not consumed in the process.

What are the light-dependent reactions of photosynthesis?

Reactions that capture light energy to produce ATP and NADPH, occurring in the thylakoid membranes.

What is the Calvin Cycle?

A process that uses ATP and NADPH to fix CO2 into glucose in the stroma of chloroplasts.

What is the overall equation for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP (~30-32 ATP).

What occurs during glycolysis?

Glucose is converted into 2 pyruvate, producing 2 ATP and 2 NADH.

What is the endosymbiotic theory?

The theory that mitochondria and chloroplasts were once independent bacteria that became part of eukaryotic cells.

What is the role of chlorophyll in photosynthesis?

It absorbs light energy, primarily in the blue-violet and red wavelengths.

What happens during depolarization?

The inside of the cell becomes less negative (more positive) due to Na+ influx.

What is the function of vacuoles in plant cells?

Storage, particularly for water and maintaining turgor pressure.

What is the role of the mitochondria?

Cellular respiration and ATP production.

What is a point mutation?

A change in a single nucleotide in the DNA sequence.

What is the significance of the surface area to volume ratio in cells?

Smaller cells have a higher SA:V ratio, allowing for more efficient nutrient exchange.

What is oxidative phosphorylation?

The process where NADH and FADH2 donate electrons to the electron transport chain, creating a proton gradient that produces ~26-28 ATP.

What is the role of oxygen in oxidative phosphorylation?

Oxygen acts as the final electron acceptor, forming water (H2O).

What happens during fermentation when oxygen is unavailable?

Pyruvate undergoes fermentation to regenerate NAD+ so glycolysis can continue, producing no additional ATP beyond the initial 2 ATP from glycolysis.

What are the two types of fermentation?

Lactic acid fermentation (pyruvate → lactate) and alcoholic fermentation (pyruvate → ethanol + CO2).

What is direct contact cell signaling?

A type of signaling where cells physically touch, such as through gap junctions in animals or plasmodesmata in plants.

What is paracrine signaling?

Local signaling where signaling molecules affect nearby cells, like neurotransmitters and growth factors.

What is endocrine signaling?

Long-distance signaling where hormones travel through the bloodstream to distant cells, such as insulin and estrogen.

What occurs during the reception stage of signal transduction?

A signal (ligand) binds to a receptor protein, causing a change in its shape.

What is the significance of phosphorylation cascades in signal transduction?

They amplify the signal, allowing one ligand to activate thousands of proteins.

What are the three stages of signal transduction?

Reception, transduction, and response.

What is negative feedback in biological systems?

A mechanism where the response reduces the original stimulus, helping maintain homeostasis.

What is positive feedback?

A mechanism where the response enhances the original stimulus, such as in blood clotting and childbirth.

What are the phases of the cell cycle?

Interphase (G1, S, G2) and mitosis (prophase, metaphase, anaphase, telophase) followed by cytokinesis.

What occurs during the G1 phase of interphase?

Cell growth, normal activities, and preparation for DNA replication.

What happens during the S phase of interphase?

DNA replication occurs, resulting in duplicated chromosomes (sister chromatids).

What is the function of checkpoints in the cell cycle?

To assess cell size, DNA integrity, and ensure proper progression through the cycle.

What are cyclins and their role in the cell cycle?

Proteins whose levels fluctuate during the cycle, activating cyclin-dependent kinases (CDKs) that regulate cell cycle progression.

What is cancer in terms of cell division?

Uncontrolled cell division that ignores regulatory checkpoints and can metastasize.

What are proto-oncogenes?

Normal genes that promote cell division; when mutated, they become oncogenes leading to excessive division.

What are tumor suppressor genes?

Genes that normally inhibit cell division; mutations can lead to loss of function and uncontrolled growth.

What is the multi-hit hypothesis in cancer biology?

The idea that cancer requires multiple mutations in both oncogenes and tumor suppressor genes.

What is the role of NADH and FADH2 in cellular respiration?

They act as electron carriers transporting high-energy electrons to the electron transport chain.

What is chemiosmosis?

The process where ATP synthase uses the proton gradient to produce ATP.

What is the importance of the proton gradient in oxidative phosphorylation?

It stores potential energy that drives ATP synthesis via ATP synthase.

What is the difference between active transport and passive transport?

Active transport requires energy to move substances against their concentration gradient, while passive transport does not.

What is the function of the sodium-potassium pump?

It actively transports sodium out of the cell and potassium into the cell, maintaining membrane potential.

What is the role of second messengers in signal transduction?

They relay signals within the cell and amplify the response to the initial signal.

What is apoptosis?

Programmed cell death that eliminates damaged or unnecessary cells.

What is the significance of understanding the cell cycle and cancer?

It helps in developing treatments and understanding the mechanisms of uncontrolled cell growth.