Chapter 1 Notes Essay

Submitted By rkuchevar
Words: 9854
Pages: 40

Chapter 1: Cell Biology
I. Prokaryotes and Eukaryotes
I. Eukaryotes
i. Cells of higher animals and plants ii. Single-celled organisms -- fungi, protozoa, & algae iii. Larger than prokaryotes iv. Have more extensive intracellular anatomy & organization (complex cellular organization)
v. Have membrane-bound organelles – intracellular compartments, includes a well-defined nucleus vi. Contain histones – proteins that bind with deoxyribonucleic acid (DNA) and are involved in coiling of DNA vii. Have several chromosomes viii. Protein synthesis differs due to major structural differences in ribonucleic acid (RNA)-protein complexes ix. Mechanisms of transport across outer cellular membranes differ, also differ in enzyme content
II. Prokaryotes
i. Cyanobacteria (blue-green algae), bacteria, and rickettsiae ii. Do not contain organelles iii. Nuclear material is not encased in nuclear membrane iv. Lack of distinct nucleus
v. Single circular chromosome in which nuclei of prokaryotic cells carry genetic info vi. Lack protein class called histones
II. Cellular Functions
 Differentiation – process by which cells become specialized so that some cells perform one kind of function and other cells perform other functions o Cells with one highly developed function (ex. movement) often lack some other property (ex. hormone production) which is more highly developed in some other specialized cell
I. Eight Chief Cellular Functions
i. Movement
1. Muscle cells can generate forces that produce motion
2. Muscles attached to bones produce limb movements
3. Muscles that enclose hollow tubes or cavities can move or empty contents when they contract
4. Example: Contraction of smooth muscle cells surrounding blood vessels changes diameter or blood vessels; contraction of muscles in walls of urinary bladder expels urine ii. Conductivity
1. Manifested by wave of excitation (electrical potential) that passes along surface of cell to reach other parts
2. Response to stimulus
3. Chief function of nerve cells iii. Metabolic Absorption
1. Cells take in and use nutrients and other substances from their surroundings
2. Cells of kidney tubules reabsorb fluids and synthesize proteins
3. Intestinal epithelial cells reabsorb fluids and synthesize protein enzymes iv. Secretion
1. Cells synthesize new substances from substances they absorb and then secrete the new substances to serve as needed elsewhere (ex. mucous gland cells)
2. Cells of adrenal gland, testes, and ovary can secrete hormonal steroids
v. Excretion
1. All cells can rid themselves of waste products resulting from metabolic breakdown of nutrients
2. Lysosomes – membrane bound sacs within cells that contain enzymes to break down and digest large molecules and turn them into waste products that are released from cells vi. Respiration
1. Cells absorb O2 which is used to transform nutrients into energy in form of adenosine triphosphate (ATP)
2. Cellular respiration (oxidation) occurs in mitochondria vii. Reproduction
1. Tissue growth occurs as cells enlarge and reproduce themselves
2. Tissue maintenance requires that new cells be produced to replace cells lost normally through cellular death
3. Not all cells are capable of continuous division viii. Communication
1. Vital for cells to survive as society of cells
2. Pancreatic cells secrete and release insulin necessary to signal muscle cells to absorb sugar from the blood for energy
III. Structure and Function of the Cellular Components of the Eukaryotic Cell
I. Three general components
i. Plasma membrane – outer cell membrane (plasmalemma) ii. Cytoplasm – fluid filling inside cell iii. Intracellular organelles – membrane bound
II. Nucleus
i. Surrounded by cytoplasm and located in center of cell ii. Largest membrane-bound organelle
1. Structures
a. Nuclear envelope
i. Comprised of two membranes ii. Outer membrane is continuous with membranes of endoplasmic reticulum iii. Inner membrane encloses