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

Plant and Animal Classification

Sperm whale - Animalia from stomata plants expel oxygen from their

Cork oak - Plantae leaves, the CO2 from respiration and excess

Crayfish - Animalia of water

Rosebush - Plantae

Starfish - Animalia the transport of substance in the plant take care

Pine tree - Plantae in the stem which travel through the vessel, branches and veins of the leaves

Iberian lynx - Animalia

Holm oak - Plantae

Gymnosperm: Angyonsperm

Seed are not in a fruit, they are in a fruit

Type of leaves: evergreen, deciduous

Flowers: hermaphrodite

Appearance: trees, shrubs, cereals

The Sounds of Language

A Guide to Phonetic Symbols

Consonants

Sensory Receptors and Sensory Nerves

Sensory Receptors

Information from the environment and internal organs is detected by sensory receptors. These receptors can be:

• Surrounded by cells (not neurons)
• Connected with a neuron (sensory nerve) in which they will generate action potentials
• Specialized to respond to one particular form of energy

There are many different types of sensory receptors:

• Mechanoreceptors - detect touch and pressure
• Thermoreceptors - detect cold and warmth
• Nociceptors - detect pain
• Electromagnetic receptors - detect light
• Chemoreceptors - detect taste, smell, blood O₂ and CO₂ concentration, blood glucose, amino acids, and fatty acids

A receptor can be excited by:

• Mechanical deformation - stretches the receptor, opening ion channels
• Application

Theories on the Origin of Life

The primordial soup hypothesis is incapable of explaining the origin of life because the early atmosphere wasn't composed of the gases described by Oparin and Haldane. Also, we know that in the early atmosphere, there was no ozone layer, so it would make the first molecules very unstable because of UV radiation. The hypothesis was supported by the Miller-Urey experiment, which consisted of the following: a mixture of gases was put in a container, and high-voltage electric shocks were applied. Then, gases were condensed in another container, simulating the primitive ocean. Finally, several organic compounds were found in that simulated "primordial soup," including amino acids. As an alternative to the primordial... Continue reading "Origin of Life and Evolution: Theories and Evidence" »

Respiration: The Energy Source of Life

Every living cell needs energy. In humans, our cells need energy for:

• Contracting muscles
• Making proteins
• Making new cells
• Cell division
• Producing heat inside the body

All of this energy comes from the food that we eat. The food is digested (broken down) and absorbed from the intestine into the blood. Then, the blood goes to the body, and the cells take the nutrients.

Aerobic Respiration

Most of the time, our cells release energy from glucose by combining it with oxygen.

Aerobic respiration involves chemical reactions in cells that use oxygen to break down nutrient molecules to release energy.

glucose + oxygen → carbon dioxide + water

Anaerobic Respiration

Anaerobic respiration involves chemical reactions in cells... Continue reading "Cellular Respiration: Aerobic vs. Anaerobic Processes" »

Chapter 1: Introduction to Cells and Microscopy

1.1 What are Living Things?

Organism: A living thing made up of cells.

Cell: The smallest living part of a living thing.

Unicellular: Single-celled organisms.

Multicellular: Organisms made of many cells.

Characteristics of All Living Things:

• Responds to its environment
• Needs energy
• Grows
• Reproduces
• Gets rid of wastes that build up in its body

Exploring the Microscopic World:

Compound Microscope: Combines two lenses to magnify objects.

Light Microscope: Uses light to view an object.

Resolving Power: The ability of a microscope to focus on two objects or details that are close together.

Magnification Power: The ability of a microscope to make an object appear larger.

Eyepiece: The lens you look through to magnify... Continue reading "Exploring the Microscopic World: Cells, Organelles, and Cellular Processes" »

DNA Mutations

Mutations are alterations to a DNA sequence that occur when a gene is damaged or changed, altering the genetic message. These mutations can have varying effects on health, depending on their location and whether they alter essential protein functions.

Mutations can occur at three levels:

1. Molecular (Gene or Point)
   • These mutations affect the chemical constitution of genes, specifically the DNA bases.
2. Chromosomal
   • These mutations affect a segment of a chromosome, altering its structure through deletions, duplications, or rearrangements.
3. Genomic
   • These mutations affect the entire genome, altering the number of chromosome sets (polyploidy or haploidy) or individual chromosomes (e.g., trisomy 21).

Mutations can be of different types:

1. Gene Mutations:

The digestive system transforms food into nutrients that are the right size to reach the body cells and be absorbed, consist of a group of organs and structures,the digestive tract and the accesory glands.