Understanding Genetics: From Mendel’s Laws to Mutations
Mendel’s Laws of Inheritance
1st Law: Law of Uniformity
When crossing two purebred individuals that differ in one character, all individuals of the first-generation offspring are identical for that character.
2nd Law: Law of Segregation
The genes determining a character separate during the formation of gametes and are reunited during fertilization.
3rd Law: Law of Independent Assortment
The genes that determine each character are inherited independently.
Key Genetic Concepts
Allele
An allele is each of the
Read MoreHuman Cell Biology: Structure, Function, Tissues, and Diseases
Human Cells: An Introduction
Human cells: The cell is the basic unit of all living beings. The human body is composed of many cells. These are eukaryotic cells, meaning they contain a nucleus. The nucleus houses DNA and is enclosed by a double membrane called the nuclear membrane. During cell division, the nuclear membrane fragments, and the genetic material compacts into chromosomes.
Organelles in Human Cells and Their Functions
The Nucleus:
Controls all cell functions through DNA.
Ribosomes:
Composed
Nervous and Endocrine Systems: Functions and Structures
The Nervous and Endocrine Systems
Interaction: Basic Life Process
The basic life process of interaction consists of a series of functions which help the body to:
- Adapt to change
- Coordinate different systems
There are two systems involved in this process:
- Nervous system
- Endocrine system
The Nervous System
The nervous system is responsible for:
- Interpreting information received from the sensory organs
- Working out appropriate responses to this information
- Sending instructions to the effectors
- Coordinating the functions
Biotic and Abiotic Factors in Ecosystems: Population Dynamics
Measuring Biotic Components of the Ecosystem
Abundance (relative representation of a species in an ecosystem) for motile organisms:
Direct Methods
- Pitfall traps: Pots buried in the soil in which animals walk into and cannot escape from.
- Homemade Pooter: Plastic straws are attached to a pot. One tube is put in the mouth: suction creates a negative pressure in the pot so that animals are drawn into it.
Indirect Methods
- Lincoln Index: The “capture-mark-release-recapture” technique. It involves:
- Collecting
Understanding Genetic Mutations: Types, Effects, and Inheritance
Mutation: A type of genetic exchange that will affect a recessive characteristic when the effect of the genetic alteration is not immediately apparent in the individual. In contrast, with a dominant characteristic, the effect of the genetic alteration is manifested in the individual.
Mutations can affect somatic cells and the organism. Note: Mutations that are produced in somatic cells, when the cell multiplies, all the daughter cells will have the mutation and form a clone. These mutations are not
Read MoreUnderstanding the Human Reproductive System
The Female Reproductive System
The female reproductive tract consists of the internal genitalia and external genitalia.
Ovaries
Two bodies located in the abdominal cavity. They form the egg or female reproductive cells, estrogen, and progesterone, hormones that regulate the sexual development of female characteristics and prepare the body for a possible pregnancy.
Reproductive Tract
Ducts and cavities that receive sperm and house the embryo. They are formed by:
The Fallopian Tubes or Oviducts
Two funnel-