Unit 2 AP Biology flashcards

What are the two main types of cells?

Prokaryotic and eukaryotic.

What distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells lack membrane-bound organelles and have DNA located in the nucleoid region.

Where is DNA located in prokaryotic cells?

In the nucleoid region, not enclosed in a nucleus.

What are some key features of prokaryotic cells?

They have ribosomes, a plasma membrane, a cell wall, and sometimes flagella.

What is the surface area-to-volume ratio critical for in cells?

It is critical for cell efficiency.

How does the surface area-to-volume ratio change as cells grow?

As cells grow, the volume increases faster than the surface area, limiting cell size.

What adaptations do cells have to increase surface area?

Flattened shapes (e.g., intestinal villi) and membrane folds (e.g., cristae in mitochondria).

What is compartmentalization in eukaryotic cells?

It allows for specialization and efficiency of cellular processes.

How do membrane-bound organelles contribute to cellular function?

They increase surface area for metabolic reactions.

What is the Endosymbiotic Theory?

It proposes that mitochondria and chloroplasts originated from engulfed prokaryotic cells.

What are some pieces of evidence supporting the Endosymbiotic Theory?

Double membranes, circular DNA, ribosomes similar to prokaryotes, and independent replication.

What are the two types of transport across cell membranes?

Passive transport and active transport.

What is passive transport?

Transport that does not require energy.

What is active transport?

Transport that requires energy (ATP) to move molecules against their concentration gradient.

What is diffusion?

The movement of molecules from an area of high concentration to an area of low concentration.

What is facilitated diffusion?

The process that uses transport proteins to help move substances down their concentration gradient.

What is osmosis?

The movement of water from an area of low solute concentration to an area of high solute concentration.

What are the types of bulk transport?

Endocytosis, exocytosis, phagocytosis, and pinocytosis.

What is endocytosis?

The process by which the cell engulfs substances.

What is phagocytosis?

A type of endocytosis where the cell 'eats' solid particles.

What is pinocytosis?

A type of endocytosis where the cell 'drinks' liquids.

What is exocytosis?

The process by which vesicles release substances outside the cell.

What is the role of aquaporins in cell membranes?

They are channel proteins that facilitate the movement of water.

What determines the rate of diffusion across a membrane?

Concentration gradient, temperature, and surface area.

What does the term 'selective permeability' mean in the context of cell membranes?

It means that the membrane regulates the entry and exit of substances.

What types of molecules require transport proteins to cross the plasma membrane?

Polar molecules and ions.

What is the function of cholesterol in the plasma membrane?

It modulates membrane fluidity.

What is the role of carbohydrates on the outer membrane of cells?

They function in cell recognition.

How do small nonpolar molecules cross the plasma membrane?

They pass easily without the need for transport proteins.

Why is the structure of the plasma membrane described as a fluid mosaic?

Because it is dynamic and composed of various proteins and lipids that can move laterally.

What are two types of cells found in living organisms?

Prokaryotic and eukaryotic.

What is a key characteristic of prokaryotic cells?

They lack membrane-bound organelles.

Where is the DNA located in prokaryotic cells?

In the nucleoid region, not enclosed in a nucleus.

How do prokaryotic cells compare in size and complexity to eukaryotic cells?

They are generally smaller and simpler.

What structures do prokaryotic cells typically possess?

Ribosomes, plasma membrane, cell wall, and sometimes flagella.

What distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells contain membrane-bound organelles.

Where is DNA enclosed in eukaryotic cells?

Within the nucleus.

In which organisms are eukaryotic cells found?

Protists, fungi, plants, and animals.

What is the role of the nucleus in a eukaryotic cell?

It contains DNA and is the site of RNA synthesis.

What is the function of ribosomes?

To synthesize proteins, found in the cytosol (free) or on the rough ER (bound).

What does the Rough Endoplasmic Reticulum (Rough ER) do?

It is studded with ribosomes and modifies proteins.

What does the Smooth Endoplasmic Reticulum (Smooth ER) synthesize?

Lipids and detoxifies drugs.

What is the primary function of the Golgi apparatus?

To modify, sort, and package proteins and lipids for secretion or internal use.

What is the main function of mitochondria?

They are the site of cellular respiration and ATP production.

What do lysosomes contain, and what is their function?

Digestive enzymes for intracellular digestion.

What is the function of the Large Central Vacuole in plant cells?

It stores water and other substances.

What does the Contractile Vacuole do in protists?

Expels excess water from the cell.

What is the role of chloroplasts in plant cells?

Site of photosynthesis, containing its own DNA.

What are the components of the cytoskeleton?

Microtubules, microfilaments, and intermediate filaments.

What is the purpose of the plasma membrane?

To act as a selectively permeable barrier.

What are amphipathic phospholipids?

Phospholipids with hydrophilic heads facing outwards and hydrophobic tails facing inwards.

How do proteins function in the plasma membrane?

They assist in transport, signal reception, cell recognition, and enzymatic activity.

What is the Fluid Mosaic Model?

It describes the plasma membrane as fluid and dynamic with cholesterol modulating fluidity.

How do carbohydrates on the outer membrane function?

They function in cell recognition.

What materials pass easily through the plasma membrane?

Small nonpolar molecules like O₂ and CO₂.

What regulates the internal environment of the cell?

Selective permeability of the plasma membrane.

What role do transport proteins play in membranes?

They help polar molecules and ions cross the plasma membrane.

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

It affects cell efficiency, with smaller cells having a higher ratio.

What adaptative features help increase a cell's surface area?

Flattened shapes and membrane folds.

What distinguishes passive transport from active transport?

Passive transport does not require energy, while active transport does.

What is diffusion?

The movement of molecules from an area of high concentration to an area of low concentration.

What is the role of aquaporins in cell membranes?

They facilitate the movement of water.