Introduction to Cell Biology and Genetics: Exercises and Solutions
EXERCISES: Biological Variability and Characters
Exercise 1
What is cytokinesis?
Solution
The distribution of cytoplasm between two daughter cells and separation of two cells.
Exercise 2
Enter the name order of the four phases of mitosis.
Solution
Four phases: prophase, metaphase, anaphase, and telophase.
Exercise 3
Identify the stage that each of the following descriptions refers to:
- Disappearance of chromosomes and chromatin appearance.
- Duplication of genetic material.
- Union of chromosomes to mitotic spindle.
Proteins: Structure, Functions, and Classification
Proteins
Amino Acids
The hydrolysis of protein molecules releases amino acids, whose union forms polypeptide chains. Amino acids have an amino group (-NH2) and a carboxyl group (-COOH).
Properties of Amino Acids:
- Amphoteric character: They behave as an acid or base depending on the pH. If the carboxyl group has an acidic character, it releases H+; if the amino group has a basic character, it accepts H+.
- Stereoisomerism: Since the alpha carbon is asymmetric, it forms stereoisomers. Two forms are considered:
Microbiology: Bacteria, Viruses, and Infections
Microbiology
Symbiotic Organisms
Symbiotic organisms are associated with other organisms, obtaining organic matter in exchange for benefits. For example, bacteria in the soil can fix atmospheric nitrogen for plants.
Parasitic Organisms
Parasitic organisms obtain organic matter from other organisms, causing disease. Examples include:
- Bacteria in aerated soils and subsoils
- Pathogenic microorganisms (disease-producing)
Louis Pasteur and Robert Koch
Louis Pasteur was a scientist who claimed that certain diseases
Read MoreGenetics: Exploring DNA, RNA, and Heredity
1. Chemical Composition of the Cell Nucleus
The cell nucleus is composed of two membranes. The inner membrane contains specific proteins that act as binding sites for chromatin and the nuclear lamina, which provides structural support. The outer membrane is continuous with the endoplasmic reticulum and has ribosomes. Key proteins within the nucleus include histones, RNA polymerase, and DNA polymerase. The nuclear pore is a complex structure made up of over 50 different proteins called nucleoporins,
Read MoreParasitism: A Comprehensive Overview
Parasitism
Definition
Parasitism is a symbiotic relationship between two species where the parasite depends metabolically on its host, deriving nutrients without providing any benefit in return. This relationship can cause varying degrees of harm to the host.
Types of Parasites
Parasitic forms exist in many biological groups, including:
- Viruses
- Bacteria
- Fungi
- Plants
- Protists (e.g., apicomplexan, some red algae)
- Animals
Parasites can be classified by their location on the host:
- Ectoparasites: Live on the host’
The Human Body: Skeletal, Muscular, and Endocrine Systems
The Skeletal System
The skeletal system is made up of bones and joints. Bones are hard, light, and strong structures that form the framework of the body and provide protection for some organs. In locomotion, bones act as rigid levers moved by muscles.
Divisions of the Skeleton
The skeleton is divided into two zones:
- Axial skeleton: Consisting of the skull, vertebral column, and thoracic cage.
- Appendicular skeleton: Consisting of the thoracic and pelvic girdles and limbs.
- Shoulder girdle: Includes two