Gen Bio 1134 Unit 2 Exam

Chapter 4 & 5

What characteristics do all cells share?

Plasma membrane (cell wall/cell membrane), cytoplasm, DNA, ribosomes

What are the key points of cell theory?

One or more cells comprise all living things, the cell is the basic unit of life, and new cells arise from existing cells.

How do eukaryotic and prokaryotic cells compare in size to each other?

Eukaryotic is larger than prokaryotic

What is the difference in organelles between eukaryotic and prokaryotic?

Eukaryotes have membrane bound organelles, DNA is located in the nucleus, may have a cell wall, are more complex

Prokaryotes are unicellular, no membrane bound organelles, have a cell wall, DNA is located in the nucleoid, smaller and simpler

What is the difference in biological macromolecules between eukaryotic and prokaryotic?

They differ in structural organization, complexity, and their specific chemical compositions

What is the difference in viruses in eukaryotic and prokaryotic?

Viruses are not living cells

Prokaryotes make up which domain(s) of life?

Archaea and Bacteria

What structure(s) enclose prokaryotic cells?

Cell wall (peptidoglycan) around the plasma membrane

Eukaryotes make up which domain(s) of life?

Eukarya

What is an organelle?

A membrane bound organ of a cell given a specific function

What eukaryotes have a cell wall and which do not?

Plant cells have one, animal does not

What are the cell walls made of?

Peptidoglycan or Cellulose (plant)

What is the function of the nucleus?

It holds genetic information and keeps them seperate from cytoplasm

What is chromatin?

A collection of DNA and associated proteins

What is a chromosome?

A thread-like structure made of protein and a single molecule of DNA that carries genetic information from cell to cell

How do items get into and out of the nucleus?

By going through the nuclear envelope

What happens at the nucleolus?

It assembles ribosomal subunits and proteins

What organelles/structures make up the endomembrane system?

Nuclear envelope, lysosomes, vesicles, endoplasmic reticulum, golgi apparatus, and plasma membrane

What are the two types of ER?

Rough ER and Smooth ER

How do we tell the difference between the two types of ER structurally?

Ribosomes are on the surface of Rough ER while there are none on Smooth ER

What happens at each type of ER?

Rough - manufacture proteins, modify/fold proteins, send out proteins to the golgi apparatus, and makes phospholipids for cell membranes

Smooth - breaks down fatty acids, makes lipids and steroid hormones, detoxifies drugs and poisons

What structure does a cell use to synthesize proteins?

Rough ER

What are the possible destinations for proteins made by bound ribosomes?

Outside the cell

What are the possible destinations for proteins made in the cytoplasm by free ribosomes?

Inside the cell

What does the Golgi apparatus look like?

Like a stack of pancakes

What happens at the Golgi apparatus?

It receives, sorts, and ships materials in vesicles

Where does cargo enter and exit the Golgi apparatus?

Enters at the cis face and leaves at the trans face of the golgi

Where can cargo go after exiting the Golgi?

It can stay inside the cell or leave the cell

How do things travel between the ER and Golgi?

By using transport vesicles

What are vacuoles?

A membrane-bound storage compartment inside a cell

What are some of the different types (and functions) of vacuoles?

Central Vacuole (found in plants), it handles water balance, waste disposal, and structural support

What is the main function of mitochondria?

Convert stored energy (macromolecule bonds) to ATP (aerobic cellular respiration)

What two compounds does the mitochondria need to carry out this function?

Glucose + Oxygen → Carbon Dioxide + Water + ATP

What are the structural parts of the mitochondria?

Cristae - inner membrane folds

Matrix - inner compartment

What is the advantage of having additional cristae?

Increases the surface area for cellular respiration

What is the main function of chloroplasts?

It is where light energy converts to chemical energy used during photosynthesis

What type of organelle is a chloroplast?

Double-membrane organelle and contains its own DNA and ribosomes

What are the structural parts of the chloroplasts?

Inner membrane - surrounds the Stroma (fluid-filled sac)

Stroma - contains interconnected membrane sacs called thylakoids

Grana/Granum - stacks of thylakoids

What types of eukaryotes contain chloroplasts?

Plant cells

What is a peroxisome?

Helps clean, detoxify, and break down (oxidizes) fatty acids and harmful substances

What are the functions of the eukaryotic cytoskeleton?

Maintain cell shape, help position organelles, provide tracks for intracellular supports, and helps with movement and cell division

What are the three components of the cytoskeleton?

Microfilaments (thinnest) , Intermediate Filaments, Microtubules (thickest)

What motor proteins are associated with each type of cytoskeleton?

Microfilament - actin, Microtubule - tubulin, Intermediate Filament - keratin

Why do we need cytoskeletal motor proteins?

They help convert chemical energy to drive movement, transport, and organization inside cells

What are cilia and flagella?

Structures for cell motility

What is the function of cilia and flagella?

Helps with cell movement

What cytoskeletal components make up cilia and flagella?

Microtubules

How is cytoskeleton components structured within cilia and flagella?

9+2 array of microtubules, spokes connect doublets to middle

What is a pseudopod?

Temporary extensions of the cell membrane and cytoplasm

What cytoskeletal component makes up a pseudopod?

Microfilaments

What are the three functions of cell-cell junctions in animal cells?

Seal, fasten, communicate

Why don’t we talk about cell-cell junctions in eukaryotes like yeast, Amoeba, Euglena, or Paramecium?

They are unicellular

What is the main type of cell-cell junction in a plant cells and what is its function?

Plasmodesmata, allows materials and signals to move directly from one plant cell to another

What components make up a membrane (like the plasma membrane) in a cell?

Carbohydrates, proteins, lipids

How are the cell membrane components arranged in the membrane?

Phospholipid bilayer (hydrophobic tails between hydrophilic heads)

What is the fluid-mosaic model?

A model showing the mixed composition of phospholipids, glycolipids, sterols, and proteins

What are some functions that proteins play in membranes?

transport, signal transduction, enzymatic activity, cell recognition, intercellular joining, attachment and anchorage

What is the difference between integral and peripheral membrane proteins?

Integral - permanently embedded within the phospholipid bilayer

Peripheral - loosely and temporarily attached to the membrane’s inner or outer surface

What is passive transport?

Naturally occurring (no energy needed) to accomplish movement

What is active transport?

Movement that requires a cell’s energy (ATP)

What is diffusion?

A passive process of transport, moves from a high concentration to a low concentration area until the concentration is equal

What is osmosis?

The movement of free water molecules through a semipermeable membrane according to the water’s concentration gradient across the membrane

What factors affect the rate of diffusion?

Difference in concentration gradient (greater difference = faster), mass (lighter = faster), temperature (hotter = faster), solvent density (density increases = decrease in diffusion), solubility (non-polar/lipid-soluble = faster), Surface area and plasma thickness (increased area = faster, increased thickness = slower), and distance (shorter = faster)

What happens to the movement of a solute when a cell is placed in a hypertonic solution?

The surrounding solute is a higher concentration and water leaves the cell

What happens to the movement of a solute when a cell is placed in a hypotonic solution?

The surrounding solute is a lower concentration and water enters the cell

What happens to the movement of a solute when a cell is placed in an isotonic solution?

Same solute concentration

What happens to the movement of water when a cell is placed in a hypertonic solution?

Water will move out

What happens to the movement of water when a cell is placed in a hypotonic solution?

Water will enter the cell

What happens to the movement of water when a cell is placed in an isotonic solution?

No net water movement (still goes in and out)

What is crenation?

The animal cell shrivels (hypertonic)

What is lysis?

Animal cell will burst (hypotonic)

What is turgor pressure?

Plant cell expands (hypotonic)

What happens to turgor pressure when you place a plant cell in a hypertonic solution?

It will decrease

What happens to turgor pressure when you place a plant cell in hypotonic solution?

It will increase

What happens to turgor pressure when you place a plant cell in an isotonic solution?

It will lessen

What is plasmolysis?

Plant cell will wilt (hypertonic)

What happens at equilibrium?

Everything is equal (no net movement)

What is facilitated diffusion?

Passive transport uses proteins to speed movement (channel protein, carrier protein)

How do channel proteins differ from carrier proteins?

Channel - hydrophilic passageways through the membrane

Carrier - bind specific substances and changes its shape to move them across the membrane

How do cells accomplish active transport?

By using ATP and going across their concentration gradient (low to high)

Why is active transport important?

It moves molecules and ions across cell membranes against the concentration gradient

How does the sodium-potassium pump work?

It uses ATP to change the pumps shape allowing ions to bind and be released ( uses ATP to maintain Na+ and K+ gradients)

What is exocytosis?

Exporting by bulk transport

What is endocytosis?

Importing by bulk transport

What is phagocytosis?

Intracellular digestion, can be performed by single-cell eukaryotes ( cell engulfs particle creating a vacuole, then fuses with a lysosome and digestion occurs, products pass into the cytosol)

What is pinocytosis?

Cell membrane invaginates, surrounds a small volume of fluid, and pinches it off (Cellular “drinking”)

What is receptor-mediated endocytosis?

The uptake of a specific substance is targeted by binding to receptors on the external surface of the membrane.

Tight junction

Type: Animal,

Function: Seal and separate bodily compartments

Examples: Intestinal tract, brain, kidney

Gap junction

Type: Animal

Function: Helps cells communicate and share molecules

Examples: Heart muscle, smooth muscle, nervous system

Desmosome junction

Type: Animal

Function: Holds cells together

Examples: Heart, lungs, muscles

Plasmodesmata junction

Type: Plant

Function: Allows materials and signals to move directly from one plant cell to another

Examples: Many plant cell connections

Mictrotubule (MT)

Subunit: tubulin

Motor Protein(s): dyneins

Functions: cell division, cell guidance, components of cilia and flagella

Microfilament (MF)

Subunit: actin

Motor Protein(s): myosin

Functions: movement, shape, and division

Intermediate Filament (IF)

Subunit: keratin

Motor Protein(s): none

Functions: strength and stability

Flagella description

Cytoskeleton Support: Microtubules (9+2 arrangement)

Functions: cell propulsion

Cilia description

Cytoskeleton Support: Microtubules (9+2 arrangement)

Functions: movement, sensory antennas

Pseudopods

Cytoskeleton Support: Actin microfilaments

Functions: movement, engulfing food

Eukaryotic cell membrane protrusions are used for?

movement