Biology chapter 7-9 quiz

What happens to a cell in a hypertonic extracellular solution?

Water moves out of the cell by osmosis, causing the cell to shrink.

What occurs in a hypotonic extracellular solution?

Water moves into the cell by osmosis, causing the cell to swell.

What is the condition of a cell in an isotonic extracellular solution?

There is no net water movement, and the cell size remains the same.

Define osmosis.

The diffusion of water through a membrane.

What is turgor pressure and why is it important for plants?

Turgor pressure is the fluid pressure that pushes the plasma membrane against the cell wall, crucial for maintaining plant structure.

Why can a plant cell survive in a hypotonic solution while a red blood cell cannot?

The plant cell has a cell wall that prevents it from bursting.

What are the main components of cell membranes?

Phospholipids and proteins.

What role do phospholipids play in membranes?

They provide the basic structure of the membrane.

What are the functions of proteins in cell membranes?

Proteins perform multiple functions, including transport and signaling.

What are integral (transmembrane) proteins?

Proteins that span the membrane and are involved in transporting selected ions and molecules.

What are the three broad classes of transport proteins?

Channels, carrier proteins (transporters), and pumps.

What is facilitated diffusion?

The process where molecules move through protein channels or carrier proteins down their concentration gradient.

What is an electrochemical gradient?

A gradient formed when ions build up on one side of a plasma membrane, allowing diffusion.

What is a gated channel?

A channel that opens or closes in response to a signal.

What are the types of signals that can open or close gated channels?

Binding of a molecule (ligand-gated), change in voltage (voltage-gated), or mechanical stimuli (stretch-gated).

What is the function of aquaporins?

They are ligand-gated channels that permit water to rapidly cross the plasma membrane.

What is the difference between passive and active transport?

Passive transport requires no energy and moves substances from high to low concentration, while active transport requires energy to move substances from low to high concentration.

What is the sodium-potassium pump (Na+/K+ - ATPase)?

An example of active transport that uses ATP to cotransport sodium and potassium ions.

What is a symporter?

A transport protein that moves two substances in the same direction across a membrane.

What is an antiporter?

A transport protein that moves one substance into the cell while moving another out.

What are the four main types of macromolecules found in cells?

Proteins, nucleic acids, carbohydrates, and lipids.

What distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells have a membrane-bounded nucleus, while prokaryotic cells do not.

What are the three domains of life based on phylogeny?

Eubacteria, Archaea, and Eukarya.

What is the function of the nucleus?

It stores and processes genetic information and contains the cell's chromosomes.

What are euchromatin and heterochromatin?

Euchromatin is lightly stained and contains actively transcribed genes, while heterochromatin is darkly stained and contains inactive genes.

What is the role of ribosomes in cells?

Ribosomes are complex machines that manufacture proteins.

What is the endoplasmic reticulum?

An organelle that is an extension of the nuclear envelope.

What are the two types of endoplasmic reticulum?

Rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).

What distinguishes rough endoplasmic reticulum from smooth endoplasmic reticulum?

Rough ER has ribosomes attached, while smooth ER lacks ribosomes.

What happens to proteins manufactured on the rough endoplasmic reticulum?

They move into the RER lumen where they are folded and processed.

What is the function of the smooth endoplasmic reticulum?

It contains enzymes that catalyze reactions involving lipids.

What is the Golgi apparatus?

A series of stacked flat membranous sacs called cisternae that modifies proteins and lipids synthesized in the ER.

What role do membranous vesicles play in the Golgi apparatus?

They carry materials to and from the organelle.

What is exocytosis?

The process by which proteins are secreted out of a cell.

What is endocytosis?

The process of bringing substances into a cell.

What are lysosomes and their primary function?

Recycling centers in animal cells that hydrolyze macromolecules and export monomers to the cytosol.

What organelles make up the endomembrane system?

Lysosomes, Golgi apparatus, and endoplasmic reticulum.

What is the sequence of protein and lipid processing in the endomembrane system?

Proteins and lipids are made in the ER, move to the Golgi apparatus for processing, and then travel to their correct destination.

What is the function of vacuoles in plant cells?

They maintain turgor pressure to support the cell structure.

What are peroxisomes and their primary function?

Membrane-bound organelles that detoxify various toxic substances and are centers of redox reactions.

What is autophagy?

The process by which lysosomes digest large cellular structures and organelles in the cytoplasm.

What are the three types of endocytosis?

Phagocytosis (large materials), pinocytosis (liquids), and receptor-mediated endocytosis (specific proteins).

What is the role of turgor pressure in plant cells?

It maintains the structure of the cell by exerting pressure against the cell wall.

What is the primary function of mitochondria in cells?

To supply most of the cell's ATP using cellular respiration.

Which organelles contain DNA in animal cells?

Nucleus and mitochondria.

Which organelles contain DNA in plant cells?

Nucleus, mitochondria, and chloroplasts.

What is the process by which chloroplasts convert CO2 and water into carbohydrates?

Photosynthesis, represented by the equation C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy (ATP).

What does the endosymbiosis theory propose?

That bacteria were engulfed by early eukaryotic cells, leading to a mutually beneficial relationship.

What is the role of the cytoskeleton in a cell?

To provide shape and structural stability, holding organelles in place and facilitating movement.

What is the function of the cell wall in plant cells?

To serve as the outer layer, with the cell membrane located just inside it.

What is metabolism?

The sum of all chemical reactions occurring in the body.

What are anabolic pathways?

Pathways that synthesize larger molecules from smaller components.

What are endergonic reactions?

Reactions that require energy input.

What are catabolic pathways?

Pathways that involve the breakdown of molecules.

What are exergonic reactions?

Reactions that release energy.

What are redox reactions?

Reactions that involve a transfer of electrons.

What is reduction in the context of cellular reactions?

A process involving a gain of electrons and potential energy, often associated with hydrogen gain.

What characterizes reduced compounds in cells?

They tend to have many C-H bonds, which have high potential energy.

What is oxidation?

The loss of electrons and potential energy, often involving loss of hydrogen.

What are common electron carriers in cellular processes?

NAD+, FAD, and NADP+.

What is the main purpose of cellular respiration?

To control the breakdown of organic molecules to produce ATP.

What are the four main steps involved in ATP production?

Glycolysis, Pyruvate Processing, TCA Cycle, and Electron Transport Chain (OXPHOS).

What is the final electron acceptor in the process of making ATP?

Oxygen.

What is the net yield of ATP, NADH, and pyruvates from glycolysis per glucose molecule?

Two ATP, two NADH, and two pyruvates.

What is substrate-level phosphorylation?

The process of producing ATP by transferring a phosphate group from an intermediate substrate to ADP.