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

Anabolic Reactions & Biomolecules

A reaction where two molecules join is anabolic and produces NH₂. Glucose and starch are carbohydrates (CH). Glucose + fructose = sucrose. Unsaturated fats increase HDL levels. An amino acid has an H and R group bonded to a carbon atom, along with NH₂ and COOH. Adenine, cytosine, guanine (thymine in DNA and uracil in RNA). Saponifiable lipids include phospholipids, fats, and waxes.

Factors Affecting Enzyme Activity

• Temperature
• pH levels
• Substrate concentration

Four Main Biomolecule Groups

Carbohydrates, lipids, proteins, and nucleic acids.

Cell Biology Concepts

Schleiden. Kingdoms with cells containing mitochondria: Animalia, Plantae, Fungi, and Protoctista. Organelles of endosymbiotic origin: mitochondria and chloroplasts.... Continue reading "Biomolecules, Genetics, and Ecology Essentials" »

Phonetics is the study of sounds made by the human vocal apparatus, used in speech. These are called speech sounds. This science tries to describe how they are made, to classify them and to give some idea of their nature. Phonetics is a more general discipline than phonology, in that it is concerned with speech sounds without reference to their function or role in any particular language.

Different branches of phonetics can be recognized. Acoustic phonetics studies the transmission of speech sounds through the air from the speaker to the hearer and is thus concerned with measuring and analyzing the movement and vibration of air. This involves investigation within the framework of physics. Auditory phonetics is the study of the hearing of speech... Continue reading "Phonetics and Phonology: Understanding Speech Sounds and Their Functions" »

Shoulder Injuries and Conditions

Glenohumeral Subluxation

Excessive translation of the humeral head without complete separation from the joint. May occur anteriorly, posteriorly, or inferiorly (most common is anterior).
Mechanism of Injury (MOI): Forced abduction and external rotation; direct blow to shoulder

Anterior Glenohumeral Dislocation

Head of humerus is forced out of its articular capsule past the glenoid and downward to rest under the coracoid process.
Injuries: Torn capsular and ligamentous tissue, possible rotator cuff and/or long head biceps tendon avulsion, possible injury to brachial plexus, possible tear (almost always a labral tear).
MOI: Direct impact to posterior shoulder, forced abduction and external rotation

Bankart Lesion

Detachment... Continue reading "Shoulder Injuries and Conditions: A Comprehensive Guide" »

Myth 1: Everything is an Adaptation Produced by Natural Selection

We tend to assume that all characteristics of plants and animals are adaptations that have arisen through natural selection. Many are neither adaptations nor the result of selection at all.

Argument 1: Not everything is an adaptation

→ Male nipples

Argument 2: Multi-Skilled Genes

We have multi-skilled genes which have more than one function.

Myth 2: Natural Selection Is the Only Means of Evolution

Before we were told all of the 10 facts were myths, we already thought this was not right, because science can also change evolution with the advanced technology we have nowadays.

Myth 3: Evolution Leads to Ever-Greater Complexity

→ No -. Evolution gets rid of what we don’t use (example:... Continue reading "Debunking Common Myths About Evolution" »

Transgenic Vaccines

Transgenic vaccines are vaccines in which an extracted gene from an organism is introduced into a unicellular organism's genetic code (a bacteria or yeast). This is done to produce a certain protein (the one from the extracted gene) and to multiply that bacteria and the production of the protein in larger quantities. That protein is then able to produce the weakened protein of the membrane of the virus.

Steps of Production

The gene is extracted from the organism and introduced into the seed of the plant, meaning it's introduced inside the first genetic information of the plant. Then you need to plant the seed and allow for the production of the protein.

Advantage of Transgenic Vaccines by Yeasts Over Injured Viruses

They stimulate... Continue reading "Introduction to Biotechnology and Evolution" »

Real and Apparent Origins

Cranial nerves have a real origin, which is the nucleus of gray substance inside the brain, except for cranial nerves I, II, and VIII, whose real origin is outside the brain. The apparent origin is the attachment surface of the brainstem.

Specific Cranial Nerves

Olfactory Nerve (CN I)

Origin: Roof of the nasal cavity.

Optic Nerve (CN II)

Origin: Ganglionic cells of the retina.

Oculomotor Nerve (CN III)

Origin: Sulcus on the medial side of the cerebral peduncle.

• Superior division: Supplies the superior rectus and levator palpebrae superioris.
• Inferior division: Supplies the medial rectus, inferior rectus, and inferior oblique muscle.
• Function: Parasympathetic innervation, constricts the pupil via the ciliary ganglion.

Trochlear

Functions of the Blood

Transports nutrients and oxygen to all the cells and collects waste products produced by cell metabolism. Contributes to the regulation of body temperature. Plays a role in the fight against infections.

Cardiovascular System

Shares nutrients and oxygen between cells and collects waste products that cells produce during metabolism.

Puberty begins with the first ejaculation (spermache) and the first menstruation (menarche).

-Menopause (50), andropause (50)

Reproductive Tract

• Epididymis: Formed by the seminiferous tubes, where sperm mature.
• Ductus referens: Continuation of the epididymis and ascends up to the abdomen. It is used to store sperm.
• Urethra: Also part of the urinary tract connecting the bladder to the exterior.

Accessory Glands

• Seminal vesicles: Flow into ductus deferens, secrete spermatic fluid.
• Prostate: Secretes prostatic fluid which consists of substances to protect sperm from the acidity of the vagina.
• Cowper's glands: A pair of glands that secrete a lubricating fluid that facilitates sexual intercourse.

Reproductive Tract

• Fallopian tubes: Two small tubes located

1. Sensory Receptors

Sensory receptors are responsible for perceiving information, which they convert into a nerve impulse. The nerve impulse travels to the brain and produces feeling.

1.1. Types of Sensory Receptors

Sensory receptors can be classified according to the stimuli that they can receive, or by where they are located.

1.1.1. According to the Stimuli

• Photoreceptors: They detect light stimuli and are located in the eye.
• Mechanoreceptors: They are stimulated by mechanical changes such as pressure, contact, or sound waves.
• Chemoreceptors: They respond to chemical changes.
• Thermoreceptors: They detect temperature changes.

1.1.2. According to Their Location

• Internal receptors: They are located in the internal organs where they collect information

Muscle Fiber

Elongated cells that make up skeletal muscle tissue

Striation

Light and dark stripes in which skeletal muscle fibers are grouped

Fascicle

Dense bundles in which skeletal muscle fibers are grouped

Voluntary Muscle

Muscle that are consciously controlled

Involuntary Muscle

Smooth muscles that cannot be consciously controlled

Myofibril

Thread-like structures found in skeletal muscle fiber

Myosin

Thick filaments that make up myofibril

Actin

Thin filaments that make up myofibril

Z Line

Structure to which actin filaments are anchored

Sarcomere

The region from one Z line to the nerve

Tendon

Fibrous connective tissue that attaches muscles to bone

Flexor

Muscle that bends a joint

Extensor

Muscle that straightens a joint

Muscle Fatigue

Physiological inability of a