Human Digestive, Respiratory, and Circulatory Systems
Digestive System
The digestive system is responsible for:
- Transporting food and breaking it down into nutrients.
- Absorbing nutrients into the bloodstream for distribution throughout the body.
- Expelling undigested waste.
Components of the Digestive System
- Gastrointestinal Tract:
- Mouth: Contains teeth and tongue.
- Pharynx: Connects the nose, middle ear, larynx, and esophagus.
- Esophagus: Muscular tube leading to the stomach.
- Stomach: Connects the esophagus and the small intestine.
- Small Intestine: Consists of
Gene Expression Control: Prokaryotes and Eukaryotes
Control of Gene Expression in Prokaryotes
The repressor produced by the regulatory gene is associated with the operator area and prevents RNA polymerase from transcribing the structural genes. This operon functions as a system of enzyme induction, in which some molecules called inducers (in this case, lactose) are associated with repressors, causing changes in their structure. Consequently, the repressors lose affinity for the operator area, and RNA polymerase transcribes the structural genes. Other
Read MoreUnderstanding Food Chains and Ecological Relationships
What is a Food Chain?
A food chain is a series of feeding relationships between organisms, indicating who eats whom.
Producers
Plants are called autotrophs because they can make their own food.
Herbivores
Herbivores are organisms that eat plant tissue, thus obtaining energy-rich molecules, which they then degrade and release the energy they need to live.
Heterotrophs
Heterotrophs are organisms that feed on other organisms.
Carnivores
Carnivores are organisms that eat other animals. These are also heterotrophs.
Read MoreGenetics: DNA, Chromosomes, and Heredity Explained
Genetics: DNA, Chromosomes, and Heredity
DNA: A DNA fragment contains the information to make a protein.
Character: Attributes, morphological or physiological, define individual species.
Qualitative Traits: Determined by a single gene, clearly distinguishable.
Quantitative Traits: Influenced by several genes, showing gradual variation among individuals in a population.
Alleles: Various alternatives of a specific gene in a population.
Homologous Chromosomes: A pair of chromosomes containing the same genes
Read MoreRespiratory System: Anatomy and Function
Air Conducting Part
The air conducting part starts in the nose and mouth and continues with the nasal cavity, pharynx, larynx, trachea, and bronchi. Function: It carries air to the lungs and has other respiratory functions.
Vocal Tract
The vocal tract constitutes the lungs and pleura. Function: Blood gas exchange.
True or False
- False – Located in the chest.
- False – The lungs are two spongy, elastic, and conical sacs located in the thoracic cavity.
- False – The right lung has 3 lobes, and the left has 2
Temperature, Tropism, Taxis, and Food Webs in Ecosystems
Temperature: Definition and Significance
Temperature is a physical quantity that expresses the degree of hotness or coldness of a substance. Generally, a hotter object will have a higher temperature. Physically, it is a scalar quantity related to the internal energy of a thermodynamic system. More specifically, it is directly related to the internal energy known as “sensitive energy,” which is the energy associated with the movement of particles in the system, whether in a translational, rotational,
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