Notes, abstracts, papers, exams and problems of Biology

DNA-RNA: Chemical Composition

Formed by deoxyribonucleotides made up of phosphate, deoxyribose, and nitrogenous bases (adenine, guanine, cytosine, thymine), and by ribonucleotides made up of phosphate, ribose, and uracil.

Molecular Structure

Double-stranded structure and single.

Types

1. Nuclear DNA found in chromatin, mitochondrial DNA in mitochondria, plastid DNA in chloroplasts.
2. Messenger (mRNA), transfer, ribosomal.

Cell Location

1. Chloroplast, mitochondria, nucleus.
2. Cytoplasm, free or associated with ribosomes.

Function

1. Contains the organism's genetic info.
2. Synthesizes proteins according to genetic info in DNA.

Replication

Molecule of DNA replicates in the nucleus.

1. The double helix of DNA opens and the strands separate.
2. Free nucleotides attach to the separated

List the Most Important Functions of Blood

• Heating: transporting or regulating body heat
• Transport nutrients and O2 to the cell
• Defense mechanism against pathogens
• Transport CO2 waste from cells
• Transport of hormones: insulin

Why the Circulatory System is Vital

• Because it keeps the cells provided with what they need and removes what they need to get rid of.
• By blood is the means by which some organs influence other organs to perform functions (HORMONES)

Identify the Main Types of Blood Vessels

Observe the Blood Components

A. CENTRIFUGATION...

PLASMA... Continue reading "Understanding the Circulatory System: Functions and Types" »

Cell Structure and Function

Cell Membrane

The cell membrane is a dynamic structure known as the fluid mosaic model, consisting of:

• Phospholipid Bilayer: Forms the basic structural framework.
• Proteins: Integral proteins (embedded in the membrane) and peripheral proteins (attached to the membrane surface).
• Cholesterol: Provides stability and regulates fluidity.
• Carbohydrates: Often attached to proteins (glycoproteins) or lipids (glycolipids) for cell recognition.

Energy Flow and Metabolism

• Energy Flow: From sunlight to producers (photosynthesis) and then through consumers (cellular respiration).
• Matter Cycling: Carbon, nitrogen, and other elements cycle through living organisms and the environment.
• Metabolism Types: Anabolism (building molecules) and Catabolism

Pharyngeal Arches

• First Arch: Mandibular nerve, Meckel's cartilage, muscles of mastication, tensor tympani, mylohyoid, anterior belly of the digastric
• Second Arch: Facial nerve, Reichert's cartilage (hyoid bone), muscles of facial expression, posterior belly of the digastric, stylohyoid, stapedius
• Third Arch: Glossopharyngeal nerve, hyoid bone, stylopharyngeus muscle
• Fourth Arch: Vagus nerve, laryngeal cartilages, soft palate muscles (except tensor veli palatini), pharyngeal muscles (except stylopharyngeus)
• Fifth Arch: Vagus nerve, no specific structure, arytenoid muscle
• Sixth Arch: Vagus nerve (recurrent laryngeal), no specific structure, intrinsic muscles of the larynx (except cricothyroid and arytenoid)

Pharyngeal Pouches

• First Pouch: Auditory tube

Microorganisms: Definitions and Characteristics

Place the correct number in the boxes to match the organism with its definition.

1. Fungus: A spore-producing organism that absorbs nutrients from the environment.
2. Protist: Any eukaryotic organism that is not an animal, plant, or fungus.
3. Bacteria: A prokaryotic organism with peptidoglycan in its cell walls.
4. Archaea: A prokaryotic organism without peptidoglycan in its cell walls.
5. Virus: A microscopic particle that cannot replicate on its own.

Understanding Hosts in Biology

A host is:

• An infected protein
• A prokaryotic organism
• A living thing that a virus or parasite uses for shelter
• A cell destroyed by a virus

Extreme Habitats of Archaea

Label these extreme habitats of Archaea with the correct names from the box:... Continue reading "Microorganisms, Reproduction, and Species Classification" »

Structural Components of Viruses

• Capsid: Protein shell that encloses a viral genome; may be rod-shaped, polyhedral, or more complex in shape
• Viral envelopes: Membrane that cloaks the capsid that in turn encloses a viral genome

Obligate Intracellular Parasites

Viruses can only reproduce within host cells because they lack metabolic enzymes, ribosomes, and other equipment for making proteins.

• Identifying host cells: "Lock and key" fit between proteins on the outside of the virus and specific receptor molecules on the host's surface (which originally evolved for functions that benefit the host).

Bacterial Defenses Against Phages

While phages have the potential to wipe out a bacterial colony in just hours, bacteria have defenses against phages:

• Natural