Module 2 Review: Cellular Basis of Life + Cell Communication

Flashcards covering cell structure, types, organelles, and basic cellular processes from lecture notes.

What are some examples of unicellular organisms?

Paramecium, Amoeba, Bacteria, and Yeast.

What is the primary difference in size between a typical eukaryotic cell and a prokaryotic cell?

A typical eukaryotic cell is 10 to 100 micrometers in diameter, while a prokaryotic cell is 1 to 10 micrometers in diameter, making eukaryotes generally bigger.

Who was the first person to observe cells, and in what year?

Robert Hooke, in 1665.

What did Matthias Schleiden contribute to cell theory?

In 1838, he stated that the cell is the fundamental unit of plant structure.

What did Theodor Schwann contribute to cell theory?

In 1839, he reported that all animal tissues also consist of individual cells.

List the three principles of cell theory.

1) All organisms are composed of one or more cells, and life processes occur within them. 2) Cells are the smallest living things and the basic units of structure and function. 3) New cells arise only by division of pre-existing cells.

Why are cells typically small in size?

To maintain a higher surface-area-to-volume ratio, which speeds up diffusion and makes the exchange of materials more efficient.

What is diffusion?

The transfer of material from a region of higher concentration to a region of lower concentration.

How do nerve cells, which are typically large, increase their surface-area-to-volume ratio to improve efficiency?

They utilize microvilli, which are tiny, finger-like structures that extend from the cell surface, increasing the surface area.

What are the three fundamental ways in which all cells resemble one another despite diverse organization?

1) Centrally located genetic material (DNA). 2) Presence of cytoplasm. 3) Presence of a plasma membrane.

Describe the primary components and appearance of the plasma membrane.

It is a thin (5-10nm) phospholipid bilayer with embedded proteins, appearing as two dark lines separated by a lighter area under an electron microscope. It has selective permeability.

What are the liquid and semifluid components of the cell called?

The cytoplasm is the semifluid matrix filling the interior of every cell, and the cytosol is its liquid component where organelles are suspended.

Name two examples of prokaryotic organisms.

Bacteria and Archaea.

How do prokaryotic cells differ from eukaryotic cells in terms of internal organization?

Prokaryotic cells lack interior organization and membrane-bound organelles, while eukaryotic cells have complex internal membranes and membrane-bound organelles.

What is the main structural component of the cell wall in bacteria, and what is its significance?

Peptidoglycan, a complex polymer of sugars and amino acids that provides a strong, resistant structure and is targeted by antibiotics like penicillin.

Name an organelle found in plant cells but missing in animal cells, and one found only in animal cells.

Chloroplasts and a cell wall are in plant cells but not animal cells. Centrioles are only in animal cells.

What is the main function of the nucleus?

It acts as the information center of the cell, containing DNA organized into chromatin and chromosomes.

Where are ribosomal RNA (rRNA) subunits synthesized within the nucleus?

In the nucleolus.

Describe the two types of endoplasmic reticulum and their primary functions.

Rough ER (RER) is disc-shaped and has ribosomes for protein synthesis. Smooth ER (SER) is tube-shaped, lacks ribosomes, and is involved in lipid synthesis, carbohydrate metabolism, detoxification, and calcium storage.

What is the function of the Golgi apparatus?

It sorts and packages proteins and is also involved in the synthesis of cell wall components in plants.

What is the role of lysosomes in a cell?

Lysosomes are membrane-bounded digestive vesicles that contain enzymes to break down biomolecules and old organelles, recycling their components.

What is the function of peroxisomes?

Peroxisomes contain the enzyme catalase, which breaks down harmful hydrogen peroxide into harmless compounds like water and oxygen.

What is the primary function of vacuoles?

Vacuoles store water and help maintain the cell's tonicity and osmotic balance. Plant cells have one large central vacuole, while animal cells have multiple small ones.

Which two organelles are primarily responsible for energy production in eukaryotic cells?

Mitochondria (metabolize sugar to generate ATP through respiration) and Chloroplasts (use light to generate ATP and sugars through photosynthesis in plant cells).

Describe the key structural features of mitochondria related to ATP generation.

Mitochondria have a double membrane, with the inner membrane folded into numerous layers called cristae, which partition the organelle and contain proteins for oxidative metabolism and ATP generation.

Where are the light-capturing photosynthetic pigments located within a chloroplast?

On the surface of the thylakoids, which are disk-shaped structures stacked into grana inside the chloroplast's inner membrane.

What is the cytoskeleton, and what protein structure helps maintain the biconcave shape of red blood cells?

The cytoskeleton is a network of protein filaments in the cytoplasm. The protein spectrin forms a scaffold connecting plasma membrane proteins to actin filaments to maintain the biconcave shape of red blood cells.

Describe the effect on a cell when it is placed in a hypertonic solution.

Water molecules move out of the cell due to a higher solute concentration outside, leading to cell shrinkage.

How do polar molecules and ions typically cross the plasma membrane?

They cannot pass through the lipid bilayer directly due to their charge; instead, they require assistance from membrane transport proteins or facilitated diffusion through specific channels (like aquaporins for water).

Distinguish between active and passive transport across a cell membrane.

Passive transport moves molecules from high to low concentration without energy. Active transport moves molecules against their concentration gradient (low to high) and requires energy, typically from ATP converted to ADP.