Key Concepts in Cellular and Nervous System Physiology
SOL.I
- If during embryonic development a defect in neural tube closure occurs, the embryo may be born with anencephaly.
- With respect to the movement of H2O through biological membranes, it is correct that it occurs down a concentration gradient of water molecules.
- Proteins A and B cross the cell membrane. If solutes X and Y are more concentrated in the extracellular medium, and X leaves the cell through A while Y enters the cell through B, it is correct that protein A is a pump and protein B is a passive
Enzymes, Nucleic Acids, and RNA Types: A Comprehensive Look
Feedback Inhibition
Feedback inhibition can be considered a form of allosteric effect. It occurs when the final metabolite of a metabolic pathway acts as an inhibitor of the first enzyme in that pathway, thereby preventing the metabolite’s own production. This effect is achieved because the final metabolite inhibitor is able to bind to the regulatory site of the first enzyme.
Enzyme Classification
- Oxidoreductases: Redox reactions involving electron loss and gain.
- Transferases: Catalyze the transfer
Protein Structure, Fatty Acids, and Metabolism: Key Concepts
Protein Primary Structure
- Consists of a sequence of amino acids.
- Peptide bonds link amino acid residues.
Protein Secondary Structure
- Stabilized by hydrogen bonds between amino and carboxyl groups of amino acids.
- Composed of regular structures and repetitive polypeptide chains.
Protein Tertiary Structure
- Stabilized by noncovalent interactions.
- Disulfide bonds confer greater thermal stability.
- Can be destabilized by chemical agents such as urea and β-mercaptoethanol.
Protein Domains
- Domains are independent
Cell Biology: Macromolecules, Processes, and Genetics
Key Concepts in Cell Biology
- Water’s hydrogen bonds give it unique properties like cohesion, adhesion, and surface tension.
- Monomers form polymers through dehydration synthesis, while hydrolysis breaks polymers into monomers.
- Nucleic acids (DNA and RNA) store genetic information and are composed of nucleotides (deoxy/ribose, phosphate, and a nitrogen base).
- Proteins are made of amino acids, and the polypeptide sequence determines their structure and function.
- Simple sugar monomers combine to form complex
Understanding Biospheres, Ecosystems, and Biomes
- What is a biosphere: The biosphere is the life zone of the Earth.
- What is an ecosystem: An ecosystem consists of the organisms that live in a particular area, the relationships between them, and their physical environment.
- What are biomes: Biomes are the large-scale ecosystems of the world.
- What is the biocenosis: It is the set of living beings in the ecosystem.
- What are biotic factors: They are the effects that other organisms have on a living being in its environment.
- What is a biotope: The biotope
Cell Cycle: Mitosis, Meiosis, and Biological Significance
Cell Cycle
The cell cycle is divided into two main phases: division (mitosis and cytokinesis) and interphase (the period between divisions).
Interphase
Interphase is the period between two successive cell divisions. It consists of the following phases:
- G1 Phase: Preparation for the S phase. This phase occurs at the end of the last division and involves preparation for DNA duplication. The restriction point in G1 determines whether the cell will proceed to the S phase.
- S Phase: Synthesis phase, involving