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

Internal Environment and the Circulatory System

1.) Internal environment: Refers to the fluids that surround the cells in the body. Conditions of the internal environment, like temperature or the composition of the fluid, must be stable for cells to work properly. This stable internal environment, called homeostasis, is maintained by the organ systems of the body.

• The internal environment consists of:
• Interstitial fluid (tissue fluid): It surrounds and bathes the cells.
• Blood and lymph: They collect and distribute substances the cells need, and eliminate waste from the cells through the circulatory system.

The lymphatic system:

• Transport absorbed fat from the small intestine to the blood.
• Defend the body as part of the immune system.

Lymphatic System

2.

How Scientists Work with DNA

It always starts with the sequence. Once the sequence is known, specific regions can be isolated, cloned, amplified, and then used to help us.

Biotechnology Methods and Applications

Biotechnology is the use of technology to change the genetic makeup of living things for human purposes. Generally, the purpose of biotechnology is to create organisms that are useful to humans or to cure genetic disorders.

Biotechnology uses a variety of techniques to achieve its aims. Two commonly used techniques are gene cloning and the polymerase chain reaction.

The Four Steps of Gene Cloning

Gene cloning is the process of isolating and making copies of a gene. Gene cloning involves four essential steps:

1. Isolation: In isolation, an enzyme

Genetic Disorders and Their Causes

Genetic disorders: Most genetic disorders are caused by mutations in one or more genes or by abnormal numbers of chromosomes.

Genetic Disorders Caused by Mutations

Some disorders are caused by mutations in autosomal genes. In the table below, there is a list of genetic disorders caused by a mutation in a single gene.

Origin of Life and Biological Evolution

Theories on Spontaneous Generation

Early experiments tested the concept of spontaneous generation:

• Francesco Redi: Rejected spontaneous generation.
• John Needham: Supported spontaneous generation (later refuted).
• Louis Pasteur: Rejected spontaneous generation using swan-neck flasks.
• Lazzaro Spallanzani: Rejected spontaneous generation.

Darwin's Observations

Species vary globally, locally, and over time.

Biological Evolution

Evolution is characterized by descent from a common ancestor and adaptation to the environment.

Hierarchy of Life Organization

1. Species
2. Population
3. Community
4. Ecosystem
5. Biome
6. Biosphere

Essential Biomolecules

Biomolecules are the fundamental building components of life.

• Carbohydrates (Carbs)

  Primary source

Digestive System: Definition and Function

Definition: Set of organs that are responsible for carrying out digestion; this is for transforming food into simple substances that pass into the blood and eliminate undigested remains. Function: Provide nutrients to cells by digesting food.

Stomach

Muscular organ 'J'-shaped, located in the abdominal cavity beneath the diaphragm. It dilates when filled with food. On its internal wall there are gastric glands which secrete gastric acid and mucus. The mucus stops the gastric acid from attacking the stomach's own walls.

Pancreas: Exocrine and Endocrine

Exocrine: It secretes pancreatic juice into the small intestine (duodenum) through the ampulla of Vater. It contains enzymes capable of digesting molecules...

Components and Dynamics of Ecosystems

Defining Ecosystem Components

• Biotope: Encompasses the non-living components of the ecosystem, such as rocks and water, or physical conditions like temperature.
• Biocoenosis: Is made up of all the living organisms that inhabit the biotope.

Interactions in the Ecosystem

• Abiotic Factors: Affect the biocoenosis (e.g., soil and low temperatures).
• Biotic Factors: Affect the biotope (e.g., herbaceous plants increasing the number of herbivores).

Adaptations to the Environment

Adaptation is an adjustment in the body or behavior of an organism to its environment.

1. Anatomical Adaptations: Physical characteristics of living things that enable them to carry out a specific activity.
2. Behavioral Adaptations: Actions that organisms

The Human Nervous System

Peripheral Nervous System (PNS)

Consists of cranial nerves and spinal nerves.

Central Nervous System (CNS)

Consists of the brain and spinal cord.

The Brain

• Cerebrum: Features left and right hemispheres with surface convolutions. It interprets sensory information and controls voluntary actions, emotions, and intellectual processes like thinking and speech.
• Cerebellum: Controls posture and balance, coordinating complex voluntary movements like walking.
• Brain Stem: Connects the brain and spinal cord, controlling involuntary actions such as heartbeat, breathing, body temperature, and sleep.

Spinal Cord

A column of nerve tissue protected by the spinal column. It connects the brain to the PNS, transmits nerve impulses, and controls...

The Excretory System

Organs Involved

• Kidneys: Eliminate toxic substances from metabolism through urine.
• Lungs: Expel CO2 derived from cellular respiration.
• Liver: Bile helps to eliminate waste through feces.
• Sweat Glands: Responsible for sweat excretion.

The Urinary System

Kidneys

• Two organs located at the back of the abdomen.
• Involved structures: Renal artery and vein.
• Primary function: Produces urine.

Urinary Tract

• Ureters
• Bladder
• Urethra

Kidney Structures

• Renal Artery: Carries blood with waste to each kidney.
• Renal Vein: Carries filtered blood away from the kidneys.

Embryonic Development and Labor Stages

• Acrosome: The tip of the sperm’s head that releases enzymes that digest egg caps.
• Cleavage: A series of cell divisions without cell growth during the first four days after fertilization.
• Morphogenesis: The process of physical change where an organism becomes several different types of cells.
• Chorion: The outermost membrane.
• Neural groove: Becomes the brain and spinal cord.
• Pharyngeal arches: Become part of the face, neck, and mouth.
• Dilation stage: The first stage of labor is the longest and involves three phases: the Early Labor Phase is the time from the onset of labor until the cervix is dilated to 3 cm.

Hormones and Their Source Organs

Match the hormone with the organ that makes it and/or its effect on the...

Population Dynamics and Carrying Capacity

Population dynamics refers to how populations change over time in response to environmental factors.

• The Carrying Capacity of a Habitat

  The carrying capacity (K) is the maximum number of individuals in a population that a specific environment can support sustainably.

• When the carrying capacity of a habitat is reached, the population size varies around that value due to two main causes:

  • Fluctuations: These are non-periodic changes caused by unpredictable environmental factors (e.g., disease, drought).
  • Cyclical Changes: These are predictable changes, such as seasonal variations (winter, spring) or the regular interaction between predators and prey populations.

Population Growth Strategies (K and R Selection)