Fungi, Viruses, Bacteria, Archaea, and Protists: Key Characteristics
Fungi: Key Characteristics
What distinguishes the fungi from other kingdoms? Fungi are eukaryotic organisms, meaning their cells have a nucleus and other organelles enclosed within membranes. Unlike plants, fungi do not perform photosynthesis. They obtain nutrients through absorption, secreting enzymes to break down complex organic matter into simpler compounds. Their cell walls contain chitin, unlike the cellulose found in plant cell walls.
What are the key physical characteristics of fungi? Fungi
Read MoreHuman Physiology: Essential Mechanisms and Functions
Blood Glucose Regulation
Rising blood glucose – Detected by insulin-secreting cells in the pancreas. The pancreas secretes insulin, causing body and liver cells to take up glucose and store it as glycogen. Glucose levels decline, and insulin release stops. Return to homeostatic blood glucose level.
Specialization of Cardiac Muscle Cells
Describe the specialization of cardiac muscle cells and how they support the electrical and mechanical functions of the heart:
- Intercalated Discs: Specialized connections
Animal Kingdom: Invertebrates and Vertebrates
Invertebrates
- Animals without an internal skeleton, although they may have an external skeleton or exoskeleton.
- Some groups with radial symmetry; we cannot draw a single axis that divides the animal into two symmetrical parts. Other groups with bilateral symmetry.
- Distinctive features for each sub-group (phylum).
Vertebrates
- Animals with an internal skeleton, or endoskeleton. It may be bone or cartilage.
- Animals with bilateral symmetry; that is, their body may be divided by an imaginary axis into two
Understanding the Endocrine System: Hormones, Glands, and Functions
The Endocrine System: An Overview
The hormonal or endocrine system consists of a set of glands, organs composed of cells that produce and secrete specific substances. These glands, made of glandular tissue, release their products in different ways. Exocrine glands secrete substances outside the body or into a cavity connected to the outside, such as sweat, salivary, and intestinal glands. Endocrine glands, on the other hand, release their products, called hormones, directly into the bloodstream.
Read MoreDNA, RNA, Mediterranean Diet, Olive Oil, and Iberian Ham
DNA and RNA: The Building Blocks of Life
DNA: is formed by the union of deoxyribonucleotides. The nitrogen bases are adenine, guanine, cytosine, and thymine.
Watson-Crick Model
- Consists of two polynucleotide chains joined together along its entire length.
- The two chains are antiparallel, with the 3′ end of one facing the 5′ end of the other.
- The union between the strands is through hydrogen bonds between the nitrogenous bases: adenine forms two bridges with thymine, and guanine forms three with cytosine.
Health, Heart Disease, and Risk Factors
Health and Quality of Life
In the mid-twentieth century, the WHO defined health as a state of complete physical, mental, and social well-being. The health of a person cannot be defined only in terms of fitness; it is necessary to consider mental health. The idea of health should not merely be the absence of disease but should be more ambitious and include positive elements. Quality of life is often used to refer to this way of understanding health.
What Determines Health?
- Lifestyle: Individual behaviors