Biology Study Guide: Key Concepts and Definitions

Biology Study Guide

Cellular Biology and Genetics

Cell Growth and Reproduction

Benign vs. Malignant Tumors

Benign tumors are characterized by slow growth, non-invasive behavior, and the absence of metastasis. Malignant tumors, on the other hand, exhibit rapid growth, invasiveness, and the ability to spread to other parts of the body through a process called metastasis.

Cancer Terminology

A carcinogen is a substance that can cause cancer. Genetics is the study of genes and their inheritance patterns. Inheritance refers to the transmission of genetic information from parents to offspring. Alleles are alternative versions of a gene. A homozygous individual has two identical alleles for a particular gene, while a heterozygous individual has two different alleles. Genotype refers to the complete set of alleles an individual possesses, while phenotype describes the observable physical and functional traits.

Dominant alleles mask the expression of their corresponding recessive alleles. Recessive alleles only manifest their effects when paired with another recessive allele.

Genetics and Inheritance

Chromosomes are structures that carry genetic information in the form of DNA. A karyotype is an organized display of an individual's chromosomes. Pedigrees are family trees that illustrate the inheritance of traits across generations. Nondisjunction is the failure of chromosomes to separate properly during cell division, leading to chromosomal abnormalities.

Ecology and Evolution

Ecological Relationships

Ecology is the study of how organisms interact with each other and their environment. An ecosystem encompasses all living organisms and nonliving components within a specific geographic area. Biodiversity refers to the variety of life on Earth, both within and among species.

Evolution is the process of change in populations over time. Homology refers to similarities between organisms that suggest a shared ancestry.

Types of Ecological Relationships

• Predation: One organism (predator) hunts and kills another organism (prey).
• Competition: Two or more organisms compete for the same resources.
• Symbiosis: A close and often long-term interaction between two different species.

Evolution and Adaptation

Adaptation is the process by which organisms develop traits that enhance their survival and reproduction in a particular environment. A population is a group of individuals of the same species living in a specific area. A community consists of populations of different species interacting with each other.

Human Impact on the Environment

Ecosystem services are the benefits that humans derive from ecosystems, such as clean air and water, pollination, and climate regulation. Environmental sustainability involves using natural resources responsibly to ensure their availability for future generations. Invasive species are non-native organisms that can disrupt ecosystems and outcompete native species.

Additional Biology Concepts

Cellular Processes

• Dysplasia: The presence of abnormal cells.
• Apoptosis: Programmed cell death.
• Hyperplasia: An increase in the number of cells in a tissue.

Genetics and Molecular Biology

• Oncogenes: Genes with the potential to cause cancer.
• Telomerase: An enzyme that maintains the length of telomeres, which are protective caps at the ends of chromosomes.
• Melanoma: A type of skin cancer.
• Genome: The complete set of genetic material in an organism.