Question

bio.1c.2 investigate to compare and contrast prokaryotic cells and eukaryotic and fungal cells.
bio.1c.3 contrast the structure of viruses with that of cells, and explain why viruses must use living cells to reproduce.
draw and label the structure of a virus.
why must viruses use living cells to reproduce?
bio.1d students will describe the structure of the cell membrane and analyze how the structure is related to its primary function of regulating transport in and out of cells to maintain homeostasis.
bio.1d.1 plan and conduct investigations to prove that the cell membrane is a semi-permeable, allowing it to maintain homeostasis with its environment through active and passive transport processes.
draw the structure of a cell membrane.
bio.1e students will develop and use models to explain the role of the cell cycle during growth, development, and maintenance in multicellular organisms.
bio.1e.1 construct models to explain how the processes of cell division and cell differentiation produce and maintain complex multicellular organisms.
draw and label the cell cycle grid chart using the terms interphase, m phase, prophase, metaphase, anaphase, telophase, cytokinesis, g1, s, & g2.
define:
somatic cells
what happens in each stage of cell division?
interphase:
g1:
s:
g2:
define and draw a simple illustration of each phase.
prophase:
metaphase:
anaphase:
telophase:

Answer:

To answer questions related to the cell wall composition table (for Bacteria, Plant, Animal, Fungal cells):

Bacteria Cell Wall:

• Presence: Yes.
• Composition: Mainly peptidoglycan (a polymer of sugars and amino acids). Some bacteria (Gram - positive) have a thick peptidoglycan layer, while Gram - negative bacteria have a thin peptidoglycan layer with an outer membrane of lipopolysaccharides.

Plant Cell Wall:

• Presence: Yes.
• Composition: Primarily cellulose (a polysaccharide made of glucose units), along with hemicellulose, pectin, and lignin (in secondary walls for structural support).

Animal Cell Wall:

• Presence: No. Animal cells have a cell membrane but lack a rigid cell wall.
• Composition: N/A (not present).

Fungal Cell Wall:

• Presence: Yes.
• Composition: Mainly chitin (a polysaccharide with nitrogen - containing groups) and glucans. Some fungi also have mannans in their cell walls.

For the question “Why must viruses use living cells to reproduce?”:

Viruses are acellular entities. They lack the cellular machinery (like ribosomes, metabolic enzymes, and energy - producing systems) required for self - replication. A virus consists of genetic material (DNA or RNA) enclosed in a protein coat (capsid, and sometimes an envelope). To reproduce, a virus must attach to a living host cell, inject its genetic material into the cell, and then use the host cell’s ribosomes, enzymes, tRNAs, and other cellular components to synthesize new viral proteins and replicate its genetic material. These new components are then assembled into new virus particles, which are released from the host cell, often destroying it in the process.

For drawing the structure of a virus:

A typical virus structure includes:

• Capsid: A protein coat made of capsomeres that encloses the viral genetic material.
• Genetic Material: Either DNA or RNA (can be single - stranded or double - stranded, linear or circular).
• Envelope (in some viruses): A lipid bilayer derived from the host cell membrane, with embedded viral glycoproteins (spike proteins) that help in attachment to host cells.

You can draw a simple diagram with a circular or polygonal capsid, a label for the genetic material inside, and if applicable, an envelope around the capsid with spike proteins.

For drawing the cell membrane structure:

The cell membrane (fluid mosaic model) has:

• Phospholipid Bilayer: Two layers of phospholipids. Each phospholipid has a hydrophilic (water - attracting) head (containing a phosphate group) and two hydrophobic (water - repelling) tails (fatty acid chains). The heads face outward (toward the aqueous environment inside and outside the cell), and the tails face inward, forming a hydrophobic core.
• Proteins: Integral proteins (span the entire bilayer) and peripheral proteins (attached to the surface of the bilayer). These proteins have functions like transport, cell - cell recognition, and enzymatic activity.
• Cholesterol (in animal cells): Embedded in the bilayer, it helps maintain membrane fluidity and stability.
• Carbohydrates: Attached to proteins (glycoproteins) or lipids (glycolipids) on the outer surface, involved in cell recognition.

For the cell cycle and cell division stages:

Interphase:

• G₁ (Gap 1): The cell grows in size, synthesizes proteins and organelles needed for normal cellular functions, and prepares for DNA replication.
• S (Synthesis): The cell replicates its DNA. Each chromosome is duplicated, resulting in two sister chromatids held together by a centromere.
• G₂ (Gap 2): The cell continues to grow, synthesizes more proteins (especially those needed for cell division), and checks for DNA damage. The cell is now ready to enter mitosis.

Mitotic Phases:

• Prophase: Chromatin condenses into visible chromosomes. The nuclear envelope breaks down, and the mitotic spindle (made of microtubules) begins to form. Centrosomes move to opposite poles of the cell.
• Metaphase: Chromosomes line up at the metaphase plate (the equatorial plane of the cell). Spindle fibers attach to the centromeres of the chromosomes.
• Anaphase: Sister chromatids separate at the centromere. The spindle fibers pull the chromatids (now called daughter chromosomes) toward opposite poles of the cell.
• Telophase: Daughter chromosomes reach the poles. The nuclear envelope reforms around each set of chromosomes, and the chromosomes decondense back into chromatin. The mitotic spindle breaks down.
• Cytokinesis: The cytoplasm divides. In animal cells, a cleavage furrow forms and pinches the cell into two. In plant cells, a cell plate forms between the two new nuclei, which develops into a new cell wall.

For the tonicity (hypotonic, isotonic, hypertonic) examples:

• Hypotonic Solution: A solution with a lower solute concentration (and higher water potential) than the cell. For example, if a plant cell is placed in distilled water (hypotonic), water enters the cell via osmosis. The plant cell becomes turgid as the central vacuole fills with water, and the cell wall prevents it from bursting.
• Isotonic Solution: A solution with the same solute concentration as the cell. For example, if a red blood cell is placed in a 0.9% NaCl solution (isotonic to human blood cells), there is no net movement of water across the cell membrane. The cell maintains its normal shape.
• Hypertonic Solution: A solution with a higher solute concentration (and lower water potential) than the cell. For example, if a plant cell is placed in a concentrated salt solution (hypertonic), water leaves the cell via osmosis. The plant cell undergoes plasmolysis, where the protoplast (cell membrane and its contents) shrinks and pulls away from the cell wall.

For the definitions:

• Somatic Cells: Body cells (all cells except gametes). These cells are diploid (contain two sets of chromosomes) and undergo mitosis for growth, repair, and asexual reproduction in unicellular organisms.
• Hypotonic: A solution with a lower solute concentration relative to another solution (usually the cell’s cytoplasm). Water moves into the cell when the cell is in a hypotonic solution.
• Hypertonic: A solution with a higher solute concentration relative to another solution (usually the cell’s cytoplasm). Water moves out of the cell when the cell is in a hypertonic solution.
• Isotonic: A solution with the same solute concentration as another solution (usually the cell’s cytoplasm). There is no net movement of water across the cell membrane.
• Passive Transport: The movement of substances across a cell membrane without the use of energy (ATP) by the cell. It occurs down a concentration gradient (from high to low concentration). Examples include diffusion (movement of small, non - polar molecules like O₂ and CO₂), facilitated diffusion (movement of polar molecules or ions via transport proteins, e.g., glucose transport into cells), and osmosis (movement of water).
• Osmosis: The diffusion of water across a selectively permeable membrane from an area of higher water potential (lower solute concentration) to an area of lower water potential (higher solute concentration).
• Diffusion: The movement of particles (atoms, molecules, ions) from an area of higher concentration to an area of lower concentration, driven by the random kinetic energy of the particles (Brownian motion).
• Facilitated Diffusion: The passive transport of substances across a cell membrane via specific transport proteins (channel proteins or carrier proteins) when they cannot cross the lipid bilayer directly (e.g., polar molecules like glucose or ions like Na⁺).
• Active Transport: The movement of substances across a cell membrane against their concentration gradient (from low to high concentration) with the use of energy (usually ATP). Examples include the sodium - potassium pump (transports Na⁺ out of the cell and K⁺ into the cell) and endocytosis/exocytosis.
• Endocytosis: A type of active transport where the cell membrane engulfs large particles or droplets of fluid, forming a vesicle. There are three types: phagocytosis (engulfing solid particles, e.g., white blood cells engulfing bacteria), pinocytosis (engulfing fluid), and receptor - mediated endocytosis (engulfing specific molecules via receptor - ligand binding).
• Exocytosis: A type of active transport where vesicles containing substances (e.g., hormones, neurotransmitters, waste products) fuse with the cell membrane, releasing their contents outside the cell.
• Phagocytosis: A form of endocytosis where a cell (phagocyte, e.g., macrophage) engulfs large, solid particles (like bacteria or cell debris) into a phagosome, which then fuses with a lysosome for digestion.
• Pinocytosis: A form of endocytosis where a cell takes in small droplets of extracellular fluid, along with the dissolved solutes, into small vesicles.

If you have specific questions about filling the tables or more detailed explanations of a particular concept, please let me know!