Understanding the Cardiovascular and Lymphatic Systems
The cardiovascular system consists of:
- A pump (the heart) that circulates fluid (blood).
- A circulating fluid (blood) containing substances and cells that need to be transported.
- A network of vessels through which blood circulates.
It has several functions:
- Transports nutrients from the digestive system to all body tissues.
- Takes oxygen from the respiratory system to cells.
- Collects waste products produced by cell metabolism.
- Takes specialized defense cells and molecules to tissues infected by pathogenic
Plant Responses, Hormones, and Development Stages
Item 2: Plant Responses, Hormones, and Development
The Relation (Stimulus-Response)
Relation is the capacity to formulate a response to a stimulus, i.e., a change that can be both internal and external to the plant. This change is detected by receptors located in the epidermis of the plant. The responses are regulated by phytohormones. Receptors are classified according to the stimuli they detect:
- Photoreceptors: Detect changes in light intensity.
- Chemoreceptors: Detect chemical changes.
- Thermoreceptors:
Cellular Respiration: Krebs Cycle, Electron Transport Chain
Krebs Cycle
The Krebs cycle is the oxidation of the acetyl group of acetyl-CoA to CO2, while reducing NAD and FAD. These reduced coenzymes are subsequently reoxidized by the respiratory chain, generating ATP. It consists of a series of eight enzymatically catalyzed reactions that occur in the mitochondrial matrix:
- Acetyl-CoA condenses with oxaloacetate to yield citrate, a tricarboxylic acid.
- Citrate is converted to isocitrate.
- Oxidative decarboxylation of isocitrate yields alpha-ketoglutarate, forming
Cell Biology: Discoveries, Theory, and Cell Types
Key Discoveries in Cell Biology
Robert Brown’s Contribution
What was the contribution of Robert Brown?
He discovered the cell nucleus through his studies of plant cells by staining the cells.
Johannes Purkinje’s Contribution
What was the contribution of Johannes Purkinje?
He identified the viscous substance (protoplasm) within cells where cell components could move.
The Cell Theory
Scientists Who Established the Cell Theory
- Scheiden Mathias (botanist): All plants are composed of plant cells.
- Schwann Theodor
Proteins, Enzymes, and Nucleic Acids
Proteins
Proteins are organic compounds composed of C, H, O, N, and S. They are large polymers made of smaller units called amino acids, which are joined by peptide bonds. The union of 1 to 12 amino acids gives rise to an oligopeptide, 12-100 forms a polypeptide, and more than 100, or if their molecular weight exceeds 5000 g/mol, constitutes a protein.
Biological Importance: Proteins are the most abundant organic compounds in cells. Their importance lies in the enormous quantity of functions they
Read MoreBacterial Cell Structures: Morphology and Functions
Living Preparations
Wet Mount
- Add a drop of the culture, and cover it with a glass slide.
- Benefits:
- It’s fast.
- Cells are alive, and you can see them in their natural shape.
- Can examine their behavior.
- Disadvantages:
- Hard to detect cells/characteristics.
- Covering the glass can damage larger cells, contaminate the observer’s fingers, dry out, and also become anoxic.
Staining
- Increases contrast and sometimes size.
- Before staining, we must let it dry and fix it. That way, the sample does not get washed off.
- Positive