Cytology — 65 Flashcards from All 4 Board Photos

Biology Unit 3 board review, October 22: 65 question-and-answer cards covering active/passive transport, diffusion, osmosis, tonicity and salt-water problems, prokaryotes, and every labeled plant-cell structure. Based on all four Classroom Board Review photos.

What is a concentration gradient?

A difference in the concentration of a substance between two areas.

What is ATP used for in cell transport?

ATP supplies the energy needed for active transport.

What is active transport?

Cell transport that requires energy (ATP). It includes protein pumps, endocytosis, and exocytosis.

Which direction do protein pumps move ions against their concentration gradient?

From LOW to HIGH concentration: uphill, against the gradient.

What is passive transport?

Movement of substances without using cellular ATP.

Which direction is the net movement during passive transport?

From HIGH to LOW concentration: downhill, with the concentration gradient.

What are the three types of passive transport on the board?

Simple diffusion, osmosis, and facilitated diffusion.

What are the three types of active transport on the board?

Protein pumps, endocytosis, and exocytosis.

What is simple diffusion?

Net movement of particles from high to low concentration. Small nonpolar molecules can pass directly through the membrane.

Which two gases can cross the cell membrane by simple diffusion?

Oxygen (O2) and carbon dioxide (CO2).

What is facilitated diffusion?

Movement from high to low concentration through a channel or carrier protein, without ATP. Examples include glucose through a carrier and ions through channels.

Does using a membrane protein automatically make transport active?

No. Facilitated diffusion uses membrane proteins but does not require ATP.

How do protein pumps work?

ATP changes the shape of a membrane protein, allowing it to move ions from low to high concentration.

What is endocytosis?

The membrane surrounds material and brings it INTO the cell inside a vesicle. It requires ATP.

What is exocytosis?

A vesicle fuses with the cell membrane and releases material OUT of the cell. It requires ATP; examples include waste removal and secretion.

What is phagocytosis?

Cell eating: a type of endocytosis in which the cell engulfs a large solid particle or another cell.

What is pinocytosis?

Cell drinking: a type of endocytosis in which the cell takes in extracellular fluid and dissolved substances in vesicles.

How is pinocytosis different from osmosis?

Pinocytosis brings fluid into vesicles using ATP. Osmosis is passive movement of water across a selectively permeable membrane.

How can you remember endocytosis vs. exocytosis?

ENDO = ENTER the cell. EXO = EXIT the cell.

Must endocytosis and exocytosis always move material from low to high concentration?

No. They are active because they use energy for vesicle transport. Low-to-high describes pumps working against a gradient.

What is osmosis?

Net movement of water across a selectively permeable membrane, from higher water concentration to lower water concentration in the class examples.

What does selectively permeable mean?

The membrane allows some substances to cross more easily than others.

What is a solute?

A dissolved substance, such as salt dissolved in water.

In these osmosis problems, water moves toward which side?

Toward the side with MORE nonpenetrating solute and LESS water. Assume water crosses the membrane but the stated solute does not.

What does hypertonic mean?

A solution has MORE solute and LESS water than the solution it is being compared with.

What does hypotonic mean?

A solution has LESS solute and MORE water than the solution it is being compared with.

What does isotonic mean?

Two solutions have equal effective solute concentrations, producing no net water movement.

What happens to an animal cell in a hypertonic solution?

Water moves OUT and the cell SHRINKS.

What happens to an animal cell in a hypotonic solution?

Water moves IN and the cell SWELLS; it may burst.

Does water stop moving in an isotonic solution?

No. Water moves in both directions at equal rates, so cell size is generally stable.

What can happen to a plant cell in a hypertonic solution?

It loses water and may plasmolyze: the membrane pulls away from the cell wall.

What happens to a plant cell in a hypotonic solution?

Water enters and the cell becomes turgid (firm). The cell wall helps prevent bursting.

Board example: the beaker has 10% salt and the cell has 1% salt. What is the beaker relative to the cell?

HYPERTONIC, because 10% salt outside is more than 1% salt inside.

Board example: the cell has 1% salt and the beaker has 10% salt. What is the cell relative to the beaker?

HYPOTONIC, because the cell has less salt than the beaker.

Board example: 99% water inside the cell and 90% water outside. Which way does water move, and what happens to the cell?

Water moves OUT, from 99% water toward 90% water. The cell loses water and SHRINKS.

A cell has 5% solute and the outside has 2%. Name the outside solution and predict water movement.

Outside is HYPOTONIC. Water moves INTO the cell; an animal cell swells.

A cell has 3% solute and the outside has 8%. Name the outside solution and predict water movement.

Outside is HYPERTONIC. Water moves OUT and the cell shrinks.

A cell has 4% solute and the outside has 4%. What happens?

The solutions are ISOTONIC. Water moves equally in both directions, with no net change in cell size.

In a simple water-plus-solute problem, a solution has 92% water. What percent is solute?

8% solute: 100% minus 92% water.

Which four structures are shared by all cells and starred in the prokaryote photo?

Cell membrane, cytoplasm, DNA, and ribosomes.

What is a prokaryote?

A unicellular organism whose cell lacks a membrane-bound nucleus and other membrane-bound organelles.

Where is a prokaryote's DNA?

In a nucleoid region of the cytoplasm, not enclosed in a nucleus. It looks like a tangled loop in the drawing.

What is the job of DNA?

It stores genetic instructions for the cell.

What does the cell membrane do?

Controls movement into and out of the cell. In the drawings, it is the thin boundary inside the cell wall.

What does the cell wall do?

Provides support, protection, and shape. It is outside the cell membrane.

What is the cytoplasm?

The interior fluid environment around cell structures, where many chemical reactions occur.

What are ribosomes, and how do they look in the drawings?

Ribosomes build proteins. They appear as small dots.

What is a flagellum?

A long, whip-like extension that helps a cell move.

What are pili?

Short hair-like structures on bacteria that help attachment; some pili help transfer DNA.

What does the nucleus do?

Contains most of a eukaryotic cell's DNA and directs cell activities. It is the large round structure in the plant-cell drawing.

What is the nuclear membrane?

The boundary surrounding the nucleus that regulates movement into and out of it.

What is chromatin?

DNA plus associated proteins; shown as thread-like material inside the nucleus.

What is the nucleolus?

The dark spot inside the nucleus that produces ribosomal components.

What is rough endoplasmic reticulum (rough ER)?

Folded membranes with attached ribosomes that help process proteins for secretion or membranes.

What is smooth endoplasmic reticulum (smooth ER)?

Membranes without ribosomes that make lipids and help with detoxification.

How can you tell rough ER from smooth ER in a diagram?

Rough ER has ribosome dots attached. Smooth ER does not.

What is the Golgi apparatus?

A stack of flattened sacs that modifies, sorts, and packages materials.

What are vesicles?

Small membrane-bound sacs that transport materials.

What do mitochondria do, and what is their visual clue?

They make most ATP during aerobic cellular respiration. Look for bean-like shapes with folded inner membranes.

What do chloroplasts do, and what is their visual clue?

They perform photosynthesis. Look for oval structures with internal stacks.

What does the central vacuole do?

Stores water and other materials and helps maintain turgor pressure. It is the large central space in the plant-cell drawing.

What is the cytoskeleton?

A network of internal fibers that supports cell shape and helps movement.

Which three features identify the plant cell in the photos?

A cell wall, chloroplasts, and a large central vacuole.

Do plant cells have mitochondria as well as chloroplasts?

Yes. Chloroplasts perform photosynthesis; mitochondria carry out aerobic respiration and produce ATP.

Does having a cell wall prove that a cell is a plant cell?

No. Bacteria and some other organisms also have cell walls. Use the full set of diagram features.