Notes, summaries, assignments, exams, and problems for Biology

Enzyme Function and Segregation

1. What is the function of amylase? What is the function of pepsin? Why are they segregated?

• Amylase: Amylase begins the digestive process by breaking down starch when you chew your food, converting it into a smaller carbohydrate.
• Pepsin: Pepsin helps digest the proteins in food.

They are segregated because amylase functions primarily in the mouth (saliva), while pepsin functions in the highly acidic environment of the stomach.

Essential Digestive Terminology

2. Definitions:

• Chyme: Is the semi-fluid mass of partly digested food that is expelled by the stomach.
• Intestinal Flora: Is the symbiotic bacteria occurring naturally in the gut.
• Defecation: Is the final action of digestion, by which organisms eliminate solid, semi-

The Significance of Meiosis

Why Meiosis?

 Meiosis generates diversity by ensuring that the gametes it gives rise to will differ genetically from one another.

 Meiosis is unlike regular cell division, or mitosis, which produces daughter cells that are exact genetic copies of parent cells.

 Evolution is spurred on by differences among offspring, and meiosis and sexual reproduction ensure such differences.

 By contrast, asexual reproduction, as is seen in bacteria and other organisms, produces organisms that are exact genetic copies, or clones, of the parental organism.

 The genetic diversity brought about by Meiosis and sexual reproduction is responsible, to a significant extent, for the great diversity of lifeforms seen in the living... Continue reading "Understanding Meiosis: The Process of Genetic Diversity and Reproduction" »

Cell Structure and Membrane Transport

9) Which component is a microfilament (actin filament) of the cytoskeleton?

C

10) Which component is a glycolipid?

B

11) Which of the following most accurately describes selective permeability?

Only certain molecules can cross a cell membrane.

12) Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?

CO2

13) Which of the following allows water to move much faster across cell membranes?

Aquaporins

14) Diffusion _____.

Is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.

15) Which of the following is true of osmosis?

In osmosis, water moves across a membrane from areas of lower solute concentration to areas

Abiotic Levels of Organization

Subatomic Level

Composed of different particles (protons, neutrons, and electrons) that form atoms.

Atomic Level

Consists of atoms of the chemical elements from which living matter is formed. The different types of atoms are represented in the periodic table according to their number of protons within their nucleus. For example:

• Nitrogen
• Carbon
• Hydrogen
• Oxygen
• Phosphorus
• Sulfur

Molecular Level

Molecules are formed by the joining of two or more atoms. This level includes both inorganic and organic molecules.

Inorganic Molecules

• Water
• Gases
• Mineral salts

Organic Molecules

• Simple sugars
• Lipids
• Nucleotides
• Amino acids

Macromolecular Level

Macromolecules are formed when molecules join together. For example, proteins are formed when amino... Continue reading "Biological Organization: Levels of Life" »

1.Which of the Following processes is endergonic?

the Synthesis of glucose from carbon dioxide and water

2.What is the Basic difference between exergonic and endergonic reactions?

Exergonic Reactions release energy; endergonic reactions absorb it.

3.Which of the Following examples is classified as a metabolic pathway?

protein Synthesis

4.When a cell Uses chemical energy to perform work, it couples a(n) ________ reaction with A(n) ________ reaction.

exergonic . . . Endergonic

5.The transfer Of a phosphate group to a molecule or compound is called

phosphorylation.

6.Anything that Prevents ATP formation will most likely

result in Cell death.

7.The energy Required to initiate an exergonic reaction is called

the energy Of activation.

8.Most of a Cell's enzymes

Vineyard Soil

The soil supports the root structure of the vine and influences the drainage levels and amount of minerals and nutrients that the vine is exposed to. The ideal soil condition for a vine is a layer of thin topsoil and subsoil that sufficiently retains water but also has good drainage so that the roots do not become overly saturated. The ability of the soil to retain heat and/or reflect it back up to the vine is also an important consideration that affects the ripening of the grapes.

Annual Cycle of a Vineyard

The annual cycle of a vineyard includes pruning, cutting, trellising maintenance, anchoring, budburst, ploughing down, de-budding, suckering, flowering, first trimming, first leaf thinning, green harvesting, 2 leaf thinning,... Continue reading "Vineyard Soil and Its Importance for Grapevine Growth" »

1. Who Discovered the Genetic Material?

Frederick Griffith

2. When Was the Genetic Material Discovered?

1928

3. What Did Frederick Griffith Do With His Major Experiment?

He studied two strains of the bacteria Streptococcus pneumoniae which causes pneumonia. He found that one strain could be transformed, or changed into the other form.

4. What Did Avery and Colleagues Identify?

They identified the molecule that transformed the R strain of bacteria into the S strain.

5. What Did Hershey and Chase Publish in 1952?

They published results of experiments that provided definitive evidence that DNA was the transforming factor.

6. How Does a Virus Replicate?

Viruses cannot replicate themselves; they must inject their genetic material into a living cell to reproduce.... Continue reading "The Structure and Function of DNA: A Comprehensive Guide" »

Understanding the Heart's Anatomy

The heart is the pump which circulates the blood throughout the body. It is approximately the size of a person's fist and is located in the chest, slightly left of center.

Myocardium: The Heart's Muscular Walls

The myocardium refers to the muscular walls that make up the heart, essential for its pumping action.

The Heartbeat and Cardiac Cycle

The heartbeat refers to the rhythmic sounds that the heart makes as it pumps blood. This rhythm can also be observed by feeling the arterial pulse. The left and right halves of the heart function as synchronized pumps, working simultaneously.

Phases of the Cardiac Cycle

The cardiac cycle describes the sequence of events that occurs during one complete heartbeat. It consists of... Continue reading "The Human Heart: Anatomy, Function, and Blood Circulation" »

blood circulation: closed: blood always circulates through the blood vessels and never leaves them. double: blood must flow through the heart twice to complete a circuit. oxygenated and deoxygenated blood never mix. they circulate through different circuits. systematic and pulmonary circuits: VI>CU>AD> VD> PUL>AI

Adaptation of Xylem to its Function

• Long, made from cells joined end to end to form tubes/vessels
• Cell walls thickened with lignin, a hard, strong material
• Lignin makes cell walls waterproof
• Cells have no cytoplasm or organelles (no cell contents)
• No end-to-end walls between cells
• Pits in the walls for water movement between vessels

Define Transpiration

Loss of water vapor from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by diffusion of water vapor through the stomata.

Leaves have many more stomata in their lower epidermis than they do in their upper epidermis, and most transpiration happens there.

Factors Affecting Transpiration

• The large internal surface area provided by the interconnecting air spaces between