Notes, summaries, assignments, exams, and exercises for Biology for Secondary education

Glossary of Genetics and Cell Biology Terms

Basic Genetic Concepts

Allele

A variant form of a gene.

Chromosomes

Threadlike structures made of DNA molecules that contain the genes.

DNA (Deoxyribonucleic acid)

A complex molecule containing the genetic information that makes up the chromosomes.

Gene

A segment of DNA on a chromosome that codes for a specific trait.

Genotype

The genetic constitution of an individual organism.

Phenotype

The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Trait

A specific characteristic of an organism.

Cell Division and Reproduction

Cell Reproduction

The process by which cells produce new cells. In many cases, this involves creating exact copies of the cells they

Accessory Digestive Glands

Salivary Glands

These glands secrete saliva into the mouth:

• Parotid: Located in front of and below the ears.
• Submaxillary (Submandibular): Located against the inner face of the lower jaw.
• Sublingual: Located on the floor of the mouth.

Pancreas: A Mixed Gland

The pancreas is an elongated, spongy gland located underneath and behind the stomach. It performs both exocrine and endocrine functions:

• Exocrine Function (Digestion): It secretes pancreatic juice into the small intestine (duodenum) through the Ampulla of Vater.
• Endocrine Function (Hormone Secretion): Secretes hormones into the blood. Example: Insulin regulates the transport of glucose inside the cells.

Liver: The Body's Largest Gland

Location: Right side of the stomach...

Human Nutrition

Human nutrition requires the coordinated function of the digestive, respiratory, circulatory, and excretory systems.

The Human Digestive System

The human digestive system involves the following processes:

• Ingestion: Intake of food.
• Digestion: Mechanical and chemical breakdown of food.
• Absorption: Transfer of nutrients from the digestive tract into the blood or lymph.
• Egestion: Elimination of substances that can't be absorbed.

Organs of the Digestive System

• Mouth: The entrance to the digestive tract.
• Pharynx: A muscular tube that connects the digestive system to the respiratory system.
• Esophagus: A muscular tube around 25 cm long; it is normally closed but opens when food is ingested.
• Stomach: Connected to the esophagus via a sphincter,

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...

Nerve Impulse Transmission Across a Synapse

The nerve impulse which has been transmitted along the membrane of the transmitter neuron reaches the end of its axon. At the end of the axon, the arrival of the nerve impulse causes neurotransmitters to be released into the synaptic cleft. Neurotransmitters bind to the membrane of the receptor neuron and generate a new nerve impulse. The new nerve impulse is transmitted along the membrane to the axon, where the whole process is repeated.

The Autonomic Peripheral Nervous System

The autonomic PNS consists of motor nerves which regulate the activity of the internal organs and control involuntary movements. The autonomic nervous system is divided into the sympathetic nervous system and the parasympathetic...

Pituitary

• Location: Head 2 lobes - anterior lobe
• Hormone: growth hormone
• Target organ: Whole body, skeleton
• Function: stimulate the growth

• Location: Head 2 lobes - anterior lobe
• Hormone: Thyroid stimulating hormone (TSH)
• Target organ: Thyroid
• Function: stimulate production of thyroid hormones

• Location: Head 2 lobes - anterior lobe
• Hormone: Gonadotropes. Follicle stimulating hormone (FSH) Luteinizing hormone (LH)
• Target organ: Ovaries and testes
• Function: action ovaries and testes

• Location: Head 2 lobes - anterior lobe
• Hormone: Adrenocorticotropic hormone (ACTH)
• Target organ: Adrenal glands
• Function: Stimulate the secretion of adrenal glands

• Location: Head 2 lobes - anterior lobe
• Hormone: Prolactin
• Target organ: breasts
• Function: stimulates breast growth and milk

The Excretory System: Function and Components

The **excretory system** is primarily composed of the kidneys, which play a central role in filtering waste from the blood. While other organs like the large intestine remove waste (feces) from the body, the excretory system specifically handles metabolic waste products dissolved in blood.

What is Excretion?

**Excretion** is the biological process of removing waste products of metabolism and other useless materials from an organism. The **kidney** is the key organ in this process, forming the core of the excretory system.

Key Components of the Excretory System

• Kidneys
• Ureters
• Bladder
• Urethra

Blood Filtration in the Kidneys

Toxin-laden blood reaches the kidneys via the **renal artery**. Within the kidneys,...

Blood

Blood is a viscous, red fluid that circulates inside the blood vessels.

An adult usually has about five liters of blood, representing 8% of their body mass. Blood volume varies with age, sex, height, and weight.

Functions of Blood

• Nutrition: Transports nutrients from the digestive system to all body cells.
• Respiration: Carries oxygen from the lungs to the cells and carbon dioxide from the cells to the lungs.
• Excretion: Collects waste products produced by cells and transports them to the excretory system for elimination.
• Defense: Carries the body's defense cells.
• Thermoregulation: Participates in the regulation of body temperature, heating or cooling.

Composition of Blood

Plasma

Plasma is a yellowish liquid, up to 90% water. It contains a variety...

1. Nutrients, Material, and Energy Source

Nutrients are the raw materials from which cells produce their own components. They replace lost components, facilitate growth, and produce new cells. Nutrients are the fuel for cells.

Other nutrients that reach the cells are used as fuel for cellular respiration. Glucose is the nutrient most used by cells as fuel. During cellular respiration, the following events occur:

• Oxygen consumption
• Release of energy usable by cells
• Production of carbon dioxide and water

Lipids and proteins can also be used as fuel to provide nutrients for energy. Cells use this energy to perform their functions.

Our body needs energy-containing nutrients to function; this energy is called chemical energy. Cellular respiration releases...

Human Tissue Types: Location and Function

Epithelial Tissue: This tissue is found on the body's exterior surfaces, lining internal cavities (such as blood vessels), and in glands. Its cells are directly linked, without any intermolecular substance between them. The primary function is to coat and protect the body's exterior and internal cavities.

Connective Tissue: Located around organs, tendons, ligaments, in the dermis of the skin, and bone marrow. It consists of several cell types and connects other organs, muscles, and bones. It also fuels the dermal tissue and generates red blood cells.

Adipose Tissue: Found under the skin and around certain organs (like the kidney or heart). It is composed of round cells that store fat. Its functions include...