Five Kingdoms of Life: Characteristics and Classification
Monera: Prokaryotes
Prokaryotes are single-celled organisms with a very simple structure. Bacteria are prokaryotes and come from more primitive groups with similar body structures. Their evolution traces back to a common ancestor, an anaerobic prokaryote.
- Cyanobacteria: Responsible for the increase of oxygen in the atmosphere thanks to their photosynthetic capacity.
Prokaryotes are classified into two major domains:
- Archaea: These bacteria live outdoors, have no murein cell wall, and their lipids are
Proteins, Amino Acids, Enzymes, and Nucleic Acids: Cellular Functions
Proteins
Proteins are the most abundant organic molecules in cells, making up 50% or more of their dry weight. They are found in all parts of all cells, as they are fundamental in all aspects of cellular structure and function. There are many different kinds of proteins, each specialized for a different biological function. Moreover, most genetic information is expressed by proteins. They belong to the class of peptides and are composed of amino acids linked together by peptide bonds. A peptide bond
Read MoreNervous and Endocrine Systems: Structure and Function
Nervous System Organization
Diffuse Network
The diffuse network, a very primitive nervous system found in polyps and jellyfish, is characterized by a network of star-shaped nerve cells distributed throughout the body. There is no cephalic region, but they have sensory organs such as statocysts for balance and ocelli for detecting light and shadow.
Cordlike Nervous System (SN Cordes)
Planaria possess a pair of nodes in the anterior region, forming a primitive brain. From this, two nerve cords run centrally
Read MoreGene Expression: From DNA to Protein Synthesis
Gene Expression
The process by which DNA directs the synthesis of proteins.
What Situation Did Archibald Garrod Suggest Caused Inborn Errors of Metabolism?
Garrod suggested that genes dictate phenotypes through enzymes that catalyze specific chemical reactions in the cell.
Describe One Example Garrod Used to Illustrate His Hypothesis
Alkaptonuria: Urine is black because it contains the chemical alkapton, which darkens upon exposure to air.
State the Hypothesis Formulated by George Beadle While Studying
Read MoreBlood Components, Functions, and Heart Mechanics
Blood Composition and Function
Blood is composed of liquid and solid elements. The liquid portion, making up 55-60% of blood, is primarily water (90%) and other substances such as glucose, proteins, enzymes, gamma globulins, minerals, gases, lipids, hormones, and vitamins. The solid portion, 40-45%, consists of:
- Red Blood Cells: Disc-shaped cells without a nucleus, numbering around 4.5 million in women and 5 million in men. They are produced in the red bone marrow and destroyed by the liver and spleen.
Cellular Respiration and Human Biology: 25 Key Questions
Cellular Respiration and Human Biology
Questions:
- Search in the dictionary for the term “synthesis.”
- What substance is oxidized in the cell during cellular respiration?
- What is the purpose of cellular respiration?
- The term “energy consumed” is generally used to refer to energy being converted to mechanical energy or into heat. Which do you think is right?
- When does the body need more energy input, in winter or summer? Why?
- Provide an example to show that during digestion there is an increase in cellular