Optical Microscopy and Cell Biology: A Practical Approach
Practice 1. First Part: Use of the Optical Microscope for the Observation of Biological Samples
The microscope’s function is threefold: 1) to produce a magnified image, 2) to separate the details, and 3) to make the details visible. The microscope includes a group of instruments that includes those made up of multiple lenses (compound microscopes) and elementary devices such as the magnifying glass (simple microscope). A typical simple microscope consists of a single biconvex lens that produces a
Read MoreGenetic Engineering and Biotechnology: Advances and Applications
Genetic Development and its Mechanisms
Genetic development has made it possible to decipher the rules governing developmental processes, such as the transformation of a fertilized ovule into an adult organism. Two Spanish scientists have helped to establish the genetic basis of this field. One of their discoveries was how animals are built in a modular form: they discovered compartments in which certain selector genes are expressed exclusively.
The development of an organism involves an initial cell
Read MoreDNA Replication and Protein Synthesis
Stages of DNA Replication
Introduction
The primosome primases open strands and start helicases, unwinding the double helix. The rest of the replisome gets together with the polymerase, forming replication forks. After opening, the DNA strands bind to SSB proteins that prevent the DNA from renaturing or forming secondary structures. Other enzymes called topoisomerases prevent kinks and the formation of super-enrollments. The DNA polymerase catalyzes the first phosphodiester bond.
Elongation
In this
Environmental Systems and Societies: Key Concepts
Definitions: Test 1
- Open system: A system that exchanges energy and matter with its surroundings.
- Closed system: A system that exchanges only energy with its surroundings.
- Isolated system: A system that doesn’t exchange anything with its surroundings.
- Transfer: Movement of energy or matter from one place to another.
- Transformation: When energy changes from one form to another.
- 1st Law of Thermodynamics: Energy cannot be created or destroyed, only transformed.
- 2nd Law of Thermodynamics: Entropy increases
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: