bio 111

What are the three parts of the Cell Theory?

1. All living things are made of cells. 2. The cell is the basic unit of life. 3. cells come from preexisting cells.

What is the smallest unit of life?

The cell

What are the minimum components of a cell?

Plasma membrane, cytoplasm, and genetic material.

Why are cells small?

To allow efficient movement of molecules across the plasma membrane; surface area doesn’t grow as fast as volume

What structures do both prokaryotes and eukaryotes share?

Plasma membrane, cytoplasm, genetic material, ribosomes, cytoskeleton.

What makes eukaryotes different from prokaryotes?

Eukaryotes have a nucleus and organelles; prokaryotes don’t

What makes prokaryotes different from eukaryotes?

Prokaryotes have a nucleoid, are always unicellular, simpler, and belong to Archaea or bacteria domains.

Which cells have a cell well?

Plant cells

Which cells have cilia & flagella?

Animal cells

Which cells have centrosomes with centrioles

Animal cells

Which cells have a central vacuole

Plant cells

What are three types of cytoskeleton filaments?

MicroFilaments (actin protein) Intermediate filaments (various proteins), Microtubules (tubulin protein)

What are the functions of the cytoskeleton?

Structural support, movement of organelles, movement of the cell

Function of the nucleus

Stores DNA, makes ribosomes, control center of cell.

Function of ribosomes?

Makes proteins

function of Endoplasmic reticulum?

Rough ER folds & modifies proteins; smooth ER makes lipids.

Function of Golgi apparatus?

Final processing, packaging, and shipping of proteins & lipids

Function of Lysosomes?

Digest food, old organelles, and invaders; can destroy cell if needed.

Function of peroxisomes?

Break down toxic molecules, fatty acids, amino acids

Function of vacuoles?

Storage; central vacuole in plants regulates water, stores nutrients, helps cell size.

Function of mitochondria?

Perform cellular respiration; make ATP from food & oxygen.

Function of chloroplasts?

perform photosynthesis; make glucose from sunlight & CO2

What do mitochondria and chloroplasts both have?

Double membranes, their own DNA, and their own ribosomes

What organelles are part of the endomembrane system?

ER, Golgi apparatus, vesicles, plasma membrane

Pathway of proteins/lipids in the endomembrane system?

ER → Vesicle -→ Golgi → vesicle → Plasma membrane or cytoplasm.

what is the endosymbiosis hypothesis?

A large prokaryote engulfed smaller prokaryotes, which became mitochondria and chloroplasts.

What evidence supports endosymbiosis?

Mitochondria and chloroplasts have their own DNA, ribosomes, and double membranes.

what external structures can bacteria have?

Cell wall, flagella, capsule, fimbriae, pili.

What internal structures do bacteria have?

Nucleoid (DNA region), cytoskeleton, ribosomes

what is the main function of the plasma membrane?

Separates cell contents from the outside and regulates what enters/exits the cell 

What model describes the plasma membrane?

The fluid mosaic model (carbs, proteins, and lipids floating together)

What are the main components of a phospholipid?

A hydrophilic head and two hydrophobic fatty acid tails.

How are phospholipids arranged in the bilayer?

Heads face watery fluids, tails face inward toward each other. 

What does cholesterol do in the plasma membrane?

Stabilizes the membrane against temperature changes (in animal cells.)

What is the function of receptor proteins?

Bind to signal molecules

What is the function of recognition proteins?

Act as “ID tags” for cells, often using carbohydrates.

What is the function of connection proteins? 

Attach a cell to other structures, including other cells. 

What is the function of transport proteins?

Control movement of molecules across the membrane.

What does selectively permeable mean?

The membrane allows some substances to pass but blocks others. 

What is a concentration gradient

A difference in concentration of a substance across a space.

What is passive transport 

Movement of molecules down the concentration gradient without energy. 

What factors make diffusion faster?

Small molecules, hydrophobic molecules, steep gradient, higher temperature, low solvent density, short distance

What is simple diffusion?

Molecules pass directly through the membrane

What is facilitated diffusion?

Transport proteins help large or hydrophilic molecules move across the membrane.

What is osmosis?

Diffusion of water across a membrane to dilute solutes that can’t cross.

What happens in an isotonic solution?

Equal concentration inside and out; no net water flow; cell stays the same.

what happens in a hypertonic solution?

Higher solute outside; water leaves cell; cell shrivels.

What happens in a hypertonic solution ?

Lower solute outside; water enters cell; cell swells.

What is turgor pressure?

Pressure in plant cells when water fills the central vacuole, pressing the membrane against the wall.

What is active transport?

Movement of molecules up the gradient using energy and transport proteins

What is endocytosis?

Membrane engulfs material into the cell using vesicles 

what is pinocytosis?

Endocytosis of fluids and dissolved substances.

What is receptor-mediated endocytosis?

Endocytosis trigged when specific molecules bind to receptors on the membrane.

What is exocytosis?

Vesicle fuses with membrane to release contents outside the cell (waste, secretions)

What are desmosomes?

Junctions that firmly join animal cells in stretchy tissues

What are tight junctions?

Junctions that stitch animal cells together to form a barrier

What are gap junctions?

channels that allow small molecules to pass between animal cells. 

What are plasmodesmata?

Pores in plant cell walls that let substances move between cells