APBio cards

What are the basic units of life?

Cells

What concept describes how organelles work together to create life?

Emergent Properties

What is the study of cells called?

Cytology

What type of cells evolved before the nuclear membrane?

Prokaryotic cells

What are the two main types of cells?

Prokaryotic and Eukaryotic cells

What is the main characteristic of prokaryotic cells?

They lack membrane-bound organelles and a nucleus.

When did the first prokaryotic cells come into existence?

About 3.5 billion years ago.

What does 'Eu' in eukaryotic mean?

True

What is the Endosymbiotic Hypothesis?

It proposes that some prokaryotes lived in symbiotic relationships, leading to the evolution of eukaryotic cells.

Who proposed the Endosymbiotic Hypothesis?

Lynn Margulis

What are two examples of organelles that support the Endosymbiotic Hypothesis?

Mitochondria and chloroplasts

What is genetic annealing?

The process of DNA segments being swapped to create a more permanent existence.

Why must cells remain small?

To maintain a high surface area to volume ratio for efficient transport of materials.

What happens to the surface area to volume ratio as cells grow?

It decreases.

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

It affects the ability to transport nutrients and waste, and the rate of heat exchange.

What are the three basic shapes of prokaryotes?

Cocci (round), Bacilli (rod), and Helical (spiral).

What is the main component of the cell wall in eubacteria?

Peptidoglycan

What is the purpose of a capsule in some bacteria?

To adhere to surfaces and protect against the immune response.

What are pili in bacteria used for?

Conjugation, movement, or attachment to surfaces.

What do eukaryotic cells have that prokaryotic cells do not?

A membrane-bound nucleus and membrane-bound organelles.

What holds the cell together in eukaryotic cells?

The plasma (cell) membrane.

What controls the activities of a cell?

The nucleus, which holds the DNA.

What is the function of ribosomes in prokaryotic cells?

To make proteins.

What is one reason larger cells struggle to survive?

They cannot transport enough nutrients and waste materials efficiently.

What is the evolutionary significance of eukaryotic cells?

They evolved from prokaryotic descendants through endosymbiosis.

What is the role of mitochondria and chloroplasts in eukaryotic cells?

Energy production and photosynthesis, respectively.

What type of reproduction do mitochondria and chloroplasts undergo?

A process similar to binary fission.

What serves as the instructions for building proteins?

DNA

Where is eukaryotic DNA located?

Within a membrane called the nuclear membrane or envelope.

What is the cytoplasm?

The fluid-filled space that contains the nucleus and other organelles.

What are membrane-bound organelles?

Enclosed structures specialized to carry out specific jobs within the cell.

What is the function of the cell membrane?

To establish and maintain internal environments different from external environments.

What does selectively permeable mean in relation to cell membranes?

The membrane allows certain materials to enter or exit while restricting others.

What is the major component of the cell membrane?

A phospholipid bilayer.

What are phospholipids?

Amphipathic molecules with hydrophilic and hydrophobic components.

What role do integral proteins play in the cell membrane?

They run completely through the bilayer and function in the transport of molecules.

What are peripheral proteins?

Proteins located on one side of the membrane that do not extend through the bilayer.

What functions do proteins in the cell membrane perform?

Molecule transport, enzyme activity, cell communication, and attachment points.

What is the role of cholesterol in the cell membrane?

To maintain membrane fluidity and prevent it from being too permeable.

What is the Fluid Mosaic Model?

A model describing the cell membrane as a moving puzzle of phospholipids and proteins.

What are the four main parts of eukaryotic cells?

Plasma membrane, nucleus, cytoplasm, and organelles.

What is the function of the nucleus?

To act as the control center for all activities performed by the cell.

What is the nuclear envelope?

A double phospholipid bilayer that encloses the DNA.

What is chromatin?

The loose and spread-out form of DNA during most of the cell's life cycle.

What is the function of the nucleolus?

To make ribosomal RNA (rRNA) and proteins for ribosome assembly.

What are ribosomes?

Cell particles made of rRNA and proteins, sites of protein synthesis.

What are free ribosomes?

Ribosomes that float freely in the cytoplasm and make proteins for use inside the cell.

What are bound ribosomes?

Ribosomes attached to the rough endoplasmic reticulum, making proteins for export.

What is compartmentalization in eukaryotic cells?

The division of the cell into distinct locations for specific metabolic processes.

What is the role of the endoplasmic reticulum?

To synthesize proteins and lipids, and to transport materials within the cell.

What is the Golgi apparatus?

An organelle that modifies, sorts, and packages proteins and lipids for secretion.

What is the function of mitochondria?

To produce energy (ATP) through cellular respiration.

What is the function of chloroplasts?

To conduct photosynthesis in plant cells.

What is the cytoskeleton?

A network of fibers that helps maintain cell shape and aids in movement.

What is the endomembrane system?

A group of membranes and organelles in eukaryotic cells that modify, package, and transport lipids and proteins.

What is the pathway for protein transport in eukaryotic cells?

Rough ER → Secretory vesicle → Golgi → Secretory vesicle → Membrane for release.

What is the function of the Rough Endoplasmic Reticulum (RER)?

It helps with protein synthesis, modification, and transport.

What is the role of the Smooth Endoplasmic Reticulum (SER)?

It aids in lipid synthesis, carbohydrate breakdown, detoxification, and storage of calcium ions.

What does the Golgi Apparatus do?

It modifies proteins by attaching sugars to them (glycosylation) and packages them for transport.

What are lysosomes and their function?

Organelles containing hydrolytic enzymes that carry out intracellular digestion and recycle materials.

What are vacuoles and vesicles used for?

They act as phospholipid-based storage containers for materials needed by the cell.

What is the primary function of mitochondria?

They perform aerobic cellular respiration to produce ATP, the energy currency of the cell.

What is the structure of mitochondria?

Mitochondria have a double phospholipid membrane with an outer smooth layer and inner folded membranes called cristae.

What is the significance of thylakoids in chloroplasts?

Thylakoids are stacked structures that increase surface area for the light-dependent stages of photosynthesis.

What is the stroma in chloroplasts?

The watery space between thylakoids where the Calvin Cycle occurs.

What are the three types of protein fibers in the cytoskeleton?

Microtubules, microfilaments, and intermediate filaments.

What is the composition of the plant cell wall?

Primarily made of cellulose, providing structural support and acting as a permeability barrier.

What is the role of spindle fibers during cell division?

They help move chromosomes during mitosis and meiosis.

How do lysosomes contribute to apoptosis?

They help in the destruction of old cells undergoing programmed cell death.

What is glycosylation?

The process of attaching sugars to proteins, which helps determine their function and destination.

What is the evolutionary significance of mitochondria?

They are believed to have descended from aerobic bacteria that formed a symbiotic relationship with larger prokaryotic cells.

What types of vacuoles exist in different cells?

Food vacuoles, contractile vacuoles, and central vacuoles.

What is the function of contractile vacuoles?

They help pump out excess water in freshwater protists.

What is the primary role of the Rough ER in protein folding?

It folds newly constructed proteins into their specific 3-D structures.

What are the components of the endomembrane system?

Includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles, and cell membrane.

What is the function of the central vacuole in plant cells?

It stores water for turgor pressure and other materials.

What is the significance of the double membrane in mitochondria?

It creates compartments for specific metabolic reactions and increases surface area for ATP production.

What provides structural support and protection to plant cells?

The cell wall, primarily composed of cellulose.

What is the composition of fungal cell walls?

Fungal cell walls are composed of chitin.

What is the extracellular matrix (ECM)?

The ECM consists of molecules secreted by a cell that provide support and regulate intercellular communication.

What is the primary function of cell transport mechanisms?

To maintain growth and homeostasis through the movement of molecules across membranes.

What is passive transport?

Transport that does not require metabolic energy and is powered by environmental energy.

Define osmosis.

The movement of water from areas of high water concentration to areas of low water concentration.

What is tonicity?

The ability of an extracellular solution to affect the movement of water into or out of a cell by osmosis.

What does osmolarity refer to?

The total concentration of all solutes in a solution.

What happens to water in a hypotonic solution?

Water moves into the cell, causing it to swell.

What is plasmolysis?

The process where the cell membrane shrivels away from the cell wall due to water loss in a hypertonic environment.

What is water potential?

A measure of the tendency of water to move from one area to another, accounting for solute concentration and pressure.

What is the formula for solute potential (ΨS)?

ΨS = -iCRT, where i is the ionization constant, C is molarity, R is the pressure constant, and T is temperature in Kelvin.

How is total water potential (ΨT) calculated?

ΨT = ΨS + ΨP, where ΨP is pressure potential.

What is the ionization constant for NaCl?

2, because it dissociates into one Na+ and one Cl- ion.

What does it mean when a cell is turgid?

It is filled with water, making the cell rigid and stiff.

What is the effect of a hypertonic solution on a plant cell?

Water leaves the cell, leading to plasmolysis and wilting.

What role do aquaporins play in cells?

They facilitate the movement of water across cell membranes.

What is the significance of maintaining osmotic balance?

It is crucial for cellular function and is a primary role of the urinary system.

What is the pressure potential (ΨP)?

The pressure exerted on the cell, which can be positive (pushing) or negative (pulling).

What happens to water potential in pure water?

The water potential is 0 in an open container.

How does water move in relation to osmolarity?

Water moves from areas of low osmolarity to areas of high osmolarity.

What is the relationship between osmolarity and tonicity?

Tonicity is influenced by the osmolarity of a solution in relation to a cell's internal environment.

What is the outcome when a plant cell with ΨT of -4.00 bars is placed in a NaCl solution with 0.20M concentration?

Water will move out of the cell, as the external solution is hypertonic.