Cell Theory, Cell Structures, and Osmosis: Biology Fundamentals

What is the cell theory?

The cell theory states that all organisms are composed of one or more cells and all cells arise from preexisting cells.

What distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells have no membrane-bound nucleus and only ribosomes for protein synthesis, while eukaryotic cells have a true nucleus and many membrane-bound organelles.

What are the basic features common to all cells?

All cells have a plasma membrane, cytoplasm, DNA, and ribosomes.

What is the function of the plasma membrane?

The plasma membrane separates the cell's contents from the environment, regulates material flow, and allows interaction with other cells.

What is cytoplasm?

Cytoplasm is all cellular parts and semi-fluid substances enclosed by the plasma membrane, excluding the region of DNA.

What role does DNA play in cells?

DNA serves as genetic material and controls the activities of the cell, with eukaryotic DNA enclosed in a nucleus and prokaryotic DNA located in the cytoplasm.

What are ribosomes responsible for?

Ribosomes are the site of protein synthesis in all cells.

What are the three shapes of bacteria?

Bacteria commonly occur in three shapes: Bacillus (rod-shaped), Coccus (spherical), and Spirilla (helical).

What is the function of the nucleus in eukaryotic cells?

The nucleus contains DNA and is enclosed by a nuclear envelope, which is a double membrane.

What is the role of the nucleolus?

The nucleolus is located inside the nucleus and is the site of ribosome production.

What is the function of the endoplasmic reticulum?

The endoplasmic reticulum is involved in the synthesis of proteins and lipids.

What does the Golgi complex do?

The Golgi complex modifies, packages, and sorts proteins and lipids for transport or export.

What are lysosomes?

Lysosomes are organelles that contain hydrolytic enzymes for intracellular digestion.

What is the function of vacuoles?

Vacuoles are membrane-enclosed sacs that function in transport, storage, and digestion of substances.

What is the role of mitochondria?

Mitochondria are responsible for ATP production and are the site of aerobic cellular respiration.

What is the function of chloroplasts?

Chloroplasts are the site of photosynthesis and contain chlorophyll.

What is the composition of cell walls in different organisms?

Cell walls are present in plants, fungi, bacteria, and some protists, composed of various substances depending on the organism.

What are the four basic tissue types in animals?

The four basic tissue types are epithelial tissue, connective tissue, muscle tissue, and nervous tissue.

What is the function of epithelial tissue?

Epithelial tissues cover the body's surface and line internal cavities and tubes.

What is connective tissue?

Connective tissues consist of sparse cells scattered through a non-living matrix and have various functions.

What is the function of muscle tissue?

Muscle tissues contract when stimulated and return to their original length.

What is the role of nervous tissue?

Nervous tissue consists of neurons that form communication lines throughout the body.

What are the unique features of an Amoeba?

Amoeba has a nucleus, pseudopodia, and vacuole.

What are the unique features of a Paramecium?

Paramecium has a nucleus and vacuole, with cilia that may or may not be visible.

What are the unique features of Spirogyra?

Spirogyra has a cell wall and chloroplasts.

What are the basic structures found in plant roots?

Plant roots contain epidermis, vascular bundles, and parenchyma.

What are the basic structures found in plant stems?

Plant stems contain epidermis, vascular bundles, and parenchyma.

What are the basic structures found in plant leaves?

Plant leaves contain epidermis, palisade cells, vascular bundles, and spongy cells.

What surrounds every cell and controls material movement?

The plasma membrane

What does it mean for a plasma membrane to be selectively permeable?

It allows some molecules to pass while blocking others.

Define diffusion.

The net movement of molecules from an area of higher concentration to an area of lower concentration.

What is a concentration gradient?

A difference in the concentration of molecules in two different areas.

How do lipid-soluble substances move across the plasma membrane?

They pass directly through the phospholipid bilayer.

How do water-soluble molecules and ions move across the plasma membrane?

They pass through pores formed by proteins (facilitated diffusion).

What is osmosis?

The diffusion of water across a selectively permeable membrane.

What determines the direction of water movement in osmosis?

The concentration of solutes in the solution.

What is a hypertonic solution?

A solution with a higher concentration of dissolved material than another solution.

What happens to a cell placed in a hypertonic solution?

Water moves out of the cell.

What is a hypotonic solution?

A solution with a lower concentration of dissolved material than another solution.

What happens to a cell placed in a hypotonic solution?

Water moves into the cell.

What is an isotonic solution?

A solution with the same concentration of dissolved material as another solution.

What happens to a cell placed in an isotonic solution?

There is no net movement of water into or out of the cell.

What is the first step in measuring osmosis in potato cells?

Weighing the potato pieces to determine their initial weight.

What does the 0.3 M solution represent in the osmosis experiment?

It has the least amount of sugar compared to the other solutions.

How do you calculate weight change in potato cells?

Final Weight - Initial Weight = Weight Change.

How do you calculate percent weight change?

Percent Weight Change = (Weight Change / Initial Weight) x 100.

What is the purpose of using control raisins in the osmosis experiment?

To compare changes in raisins placed in different solutions.

What type of solution is distilled water in relation to the raisin cells?

Hypotonic, causing the raisin to swell.

What type of solution is corn syrup in relation to the raisin cells?

Hypertonic, causing the raisin to shrink.

What is the expected outcome for raisins in a hypotonic solution?

They will swell as water enters the cells.

What is the expected outcome for raisins in a hypertonic solution?

They will shrink as water exits the cells.

What is the significance of observing changes in the raisins?

It demonstrates the principles of osmosis and the effects of different solute concentrations.

What chemical is used to detect the presence of CO2 in the experiment with humans?

Bromothymol blue, which turns from blue to green and then yellow as CO2 concentration increases.

What happens to bromothymol blue when CO2 is produced by humans?

It turns yellow as the CO2 concentration increases.

How do yeast produce CO2 during respiration?

Yeast convert pyruvic acid into ethanol and CO2 during alcoholic respiration.

What is the purpose of the balloon in the yeast experiment?

The balloon inflates as CO2 is released by the yeast using glucose.

What is the role of potassium hydroxide (KOH) in measuring oxygen uptake by beans?

KOH absorbs the CO2 produced, allowing measurement of oxygen consumption by the beans.

What structure in chloroplasts is responsible for photosynthesis?

Thylakoids, which contain chlorophyll molecules.

What are grana in chloroplasts?

Stacks of thylakoids.

What organelles in potato cells store starch produced during photosynthesis?

Leucoplasts.

What color does iodine turn when it reacts with starch?

Dark purple.

What is produced during photosynthesis that causes leaf disks to float?

Oxygen.

What is the purpose of sodium bicarbonate in the photosynthesis experiment with leaf disks?

It provides CO2 and water necessary for photosynthesis.

What technique is used to separate plant pigments?

Paper chromatography.

Which pigment is the most soluble and moves the fastest in chromatography?

Carotenes.

What pigments are typically found in plant leaves?

Chlorophyll-a, chlorophyll-b, carotenes, and xanthophylls.

How does the respirometer measure oxygen consumption in beans?

As oxygen is consumed, the dye bubble moves toward the respirometer, indicating the volume of oxygen used.

What is the main function of chloroplasts in plants?

They are the site of photosynthesis.

What happens to leaf disks when they are exposed to sunlight during photosynthesis?

They produce oxygen and begin to float in the solution.

What is the end product of glycolysis that yeast convert during respiration?

Pyruvic acid (or pyruvate).

What is the significance of CO2 production in the yeast experiment?

It demonstrates the process of alcoholic respiration and helps inflate the balloon.