Notes, summaries, assignments, exams, and problems for Biology

What Makes a Living Thing ‘Living’?

Non-Living Things

Non-living things are made up of inorganic matter. The most abundant chemical elements that make up inorganic matter are: oxygen (O), silicon (Si), aluminum (Al), and iron (Fe).

Living Things

All living things, also called organisms, are made up of the same chemical elements.

The elements that form part of living matter are known as bioelements.

The six most abundant bioelements are: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), and sulfur (S). They make up more than 90% of living matter. The atoms and molecules of bioelements combine with each other through chemical reactions, producing biomolecules. Biomolecules may be:

• Inorganic, such as water and mineral salts.
• Organic

Benefits of Plant Cloning

Plant cloning offers several significant advantages for growers:

• Fixed Genotype & Uniformity: Cloned plants retain their exact genetic characteristics, ensuring uniformity in size, growth rate, flowering time, and harvesting time.
• Shortened Time to Flower/Fruit: Clones often mature faster than seed-grown plants.
• Improved Vigor: Plants propagated from cuttings are frequently fuller and stockier.

Methods of Producing Plant Clones

The primary method involves vegetative propagation directly from a mother plant.

Plant Clone Mutation

Mutations in plant clones can be spontaneous (e.g., bud sports) or induced, such as through radiation (gamma rays), as seen in some poinsettia varieties. Mutations that result in dwarfing, variegation,... Continue reading "Mastering Plant Propagation: Cloning & Grafting Techniques" »

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-CN 9+10 Dx:-Lesion CN 5(sensory nuclei)-CN 9 lesion!-Malingnant brain glioma

***T/F:

-CS tract(NOT ) onl from Frontal-BS lesion--->controlateral hemiparesis(T)-Bilateral amr paralysis, Central cord(T)-controlateral Focal

Key Concepts in Evolution

Species: A set of individuals that can reproduce with each other and create fertile offspring.

Speciation: A process driven by several factors:

• Natural selection: Natural selection favors some individuals over others.
• Genetic isolation: Members of two different populations within the same species can no longer reproduce with the other population.
• Gradual differentiation: After isolation, populations become increasingly different.
• Speciation: Over time, genetic changes produce such significant differences that it's no longer possible for two populations to produce fertile offspring.

Human Ancestors

• Australopithecus (6 million years ago): The first hominid, walked upright.
• Homo habilis (2.5 million years ago): Used rudimentary

Interaction and Homeostasis

Interaction includes a series of processes whose object is to adapt the body to changing conditions in the internal and external environment. It connects and coordinates the different parts of our body so that they work together.

Homeostasis is the process that maintains the body's stability when there are changes in the internal environment. This process works as a feedback device, meaning that when a variation is detected in a particular element, a series of mechanisms in the body start up to make the variation return to its normal state.

Systems Participating in the Interaction Process

• Sensory Organs: Capture the stimulus, which is transformed into a nerve impulse and transmitted to the nervous system.
• Nervous System:

Steroid Hormones

Steroid hormones are a type of hormone consisting of four rings made of carbon atoms. They are derived from cholesterol and have three primary modes of action:

• Binding to membrane receptors
• Binding to and activating proteins in the cytoplasm
• Acting on receptors linked to chromosomes

Sex Hormones

Gonadal steroid hormones are produced by the gonads, which include the ovaries and testes. These hormones include:

• Androgens (e.g., testosterone, dihydrotestosterone)
• Estrogens
• Progesterone

It is important to note that gonads can produce both types of hormones, with the aromatase enzyme mediating conversions between them.

Organizing Effects of Sex Hormones

Organizing effects refer to the hormonal effects on the brain and genitals that occur during... Continue reading "Steroid and Sex Hormones: Organizing and Activating Effects" »

Saturated Fats

Carbon atoms fully saturated with hydrogen atoms. (meats, animal fats, lard, whole milk, butter, cheese, ice cream, coconut oil, palm oil)

Trans Fatty Acids

Solidified fat forms by adding hydrogen to MUFA and PUFA to increase shelf life

Osteoporosis

Condition of softening, deterioration, or loss of bone mineral density that leads to disability, bone fractures, and even death from medical complications

Protein

Classification for nutrients consisting of complex organic compounds containing nitrogen and forms by combinations of amino acids; the main substances used in the body to build and repair tissues

Amino Acids

Chemical compounds that contain nitrogen, carbon, hydrogen and oxygen; the basic building blocks the body uses to build different... Continue reading "Understanding Nutrition: Fats, Proteins, Vitamins, and Minerals" »

This document outlines the defining features of various biological phyla, including protists, algae, and fungi-like organisms, highlighting their unique characteristics and ecological roles.

Phylum Apicomplexa

Unicellular parasites of vertebrates, known for possessing non-photosynthetic plastids (apicoplasts) essential for fatty acid synthesis.

Phylum Bacillariophyta

Non-motile freshwater and marine diatoms, known for glistening when sunlight hits them.

Phylum Chlorophyta

Commonly known as green algae, possessing the same types of chloroplasts as plants.

Phylum Chrysophyta

Marine and freshwater algae, known for their golden and brown carotenoids. Also called Golden Algae.

Phylum Ciliophora

Ciliated protozoans, known for having both a macronucleus and... Continue reading "Diverse Phyla: Key Characteristics of Protists & Algae" »

Key Structures of the Digestive System

Small Intestine Structures

The villi of the small intestine project into the intestinal cavity, greatly increasing the surface area for food absorption and aiding digestive secretions.

Microvilli: Are microscopic cellular membrane protrusions that increase the surface area of cells and minimize any increase in volume. They are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction.

Ileocecal Valve: Is a sphincter muscle valve that separates the small intestine and the large intestine. Its critical function is to limit the reflux of colonic contents into the ileum.

The Large Intestine

The large intestine, also called the colon or the large bowel, is... Continue reading "Digestive System Anatomy, Nutrient Absorption, and Common Disorders" »

1. The Circulatory System

The circulatory system carries substances via the blood, which circulates through the blood vessels and is pumped by the heart.

1.1 Blood

Human blood is a thick, red liquid composed of plasma and blood cells.

Types of Blood Cells:

• Red Blood Cells: Small cells without a nucleus. They are the most numerous in the body and contain iron. This protein helps transport oxygen and carbon dioxide.
• White Blood Cells: Larger and less numerous. They defend our bodies against pathogens and tumor cells.
• Platelets: Are not true cells, but pieces of cytoplasm. They help our bodies to clot.

The Functions of Blood:

• Transport Substances: Transport nutrients and waste substances.
• Regulates Body Temperature: Maintain body temperature by distributing