Question

Thinking Questions: Some of these questions may require the use of your brain, the Internet and/or your textbook! Do your best AND do not leave any blanks! 1. What distinguishes a Eukaryotic Coll from a Prokaryotic Coll? Include all differences. 2. Why can't a cell be as big as a HOUSE? (a human house, don't be a smart aleck). Explain your answer. 3. What is a cell wall? Why do plants need cell walls? And, what are they composed of? 4. What is Cell Theory? What are all of the parts of the cell theory? 5. What are the components of a cell membrane? Why is each important to the function of the cell membrane?

Answer 1

2. If a cell gets too large then Surface to Volume ratio gets smaller as the cell gets larger.

When a cell grow in size its volume increases more than its surface ;a stage will reach when surface area becomes insufficient to draw nutrients and for the cell, it would be more difficult to get sufficient amount of oxygen and waste products out.

Thus,if a cell goes beyond a certain limit ,not enough material will be able to cross the membrane fast enough to accommodate the cellular volume.To accomplish the requirements,Cell division occurs.

3. Cell wall is a non-living rigid structure which is formed as an outer covering for the plasma membrane of Bacteria,Fungi, Algae and Plants.

Plant cells are actively involved in water transportation and the cell wall ensures that cell doesn't burst due to turgor pressure.

Cell wall also provides :Structural and mechanical support,

Helps in cell to cell interaction,Gives shape to the cell,Provides barrier to undesirable molecules.

Cell wall is composed of : ​​​​​​

In algae:Cellulose,galactans,mannans,and minerals like calcium carbonate.

In plants: Cellulose(main constituent), hemicellulose,pectin ,lignin,cutin,suberin.

4. Cell theory is a fundamental theory in biology which states that cell is the fundamental, structural and functional unit of living matter.

The theory includes:

a.All organism are composed of cells and products of cells

b.all cells arise from pre-existing cells

5.Cell membrane act as semipermeable membrane and protects intracellular components from extracellular environment and mediates cellular processes by regulating the materials that passes through the membrane.

The major components of cell membrane are:

Phospholipid(40%)-Critical component of cell memb.

Act as barrier to the passage of molecules and ions into and out of the cell

Proteins(58-59%)-Peripheral protein-Superficially arranged on the surface of lipid bilayer and have enzymatic activity.

Integral protein- Tightly binds with phospholipid.Also called tunnel protein which provide a passage for movement of water soluble material across the membrane.

Carbohydrates(1-2%)-Sugars glycolipids and glycoprotein are involved in cell to cell recognition mechanism.

Best example of cell recognition include fertilisation (sperm and egg recognize to each other) and blood-antigens.

Hope this will help you. Thank you.  

70s type 80s type & . Characters Prokaryotic cell Eukaryotic cell * Nulleen membrane Absent Present Incipient nucleus/ Nucleus well organise Genophore present * Cell organelles Membraww cell organelles Membranous cell organally are absentſlike Mitochondria Present plastid, ER, Golgibody, Microbocy) (plastid only in Plan x Ribosome 705 (Mitochondriaf present in I Mesosomes * Respiratory chloroplast Found in cytoplasm & oo in cell membrane. Mitochondria. * Chrom-owo nies Naked or folded genome Moue chromosomes. made by mainly circular (Histone associated ) do-ANA (CG-c) Rich ] (with DNA Histone protein Absent a ploidy level Haploid Haploid, Diploid, Polyploid. * Vacuoles Sap vacuole absent Present as sap vacuoles but gas vacuole . in plant cell. - present * Example Bacteria, Cynobacteria (OGA), Mycoplasma EPPLO), Altinoneycetes, ater All plants & Animal cells, Protista & fungi Monera kingdom