Biology Chapter: Cells and Biomolecules

Learning Outcomes

• Students will recognize the diversity of biomolecules like DNA, RNA, and proteins.
• Students will understand haematopoiesis as a process.
• Students will learn about cytokines and hormones involved in blood cell production.
• Students will appreciate the role of erythropoietin.
• Students will understand the relationship between myoglobin and haemoglobin structure and function.

The Cell

• All living things are composed of cells.
• Cells have similarities but also differences, such as the cell wall in plants.
• Cells are the basic unit of life.
• Cells contain organelles, proteins, etc.; some are common to all cells, while others are specialized for specific functions.

Cell Organelles

• A diagram of a cell with labeled organelles is presented (numbers 1-13).

Cell Cycle

• The cell cycle is represented as a circle with different phases labeled: G1, S, G2, and M phase.
• Key events in each phase include gap phases (G1 and G2), DNA replication (S phase), and mitosis/cytokinesis (M phase).

DNA to Chromosomes

• DNA is a double helix.
• DNA's structure is a spiral ladder-like shape.

DNA Replication

• DNA replication is based on preferential nucleotide pairing (A-T, G-C).
• This pairing makes each strand a template for the complementary strand.
• DNA acts as a template for its duplication, resulting in two chemically identical strands

Key Concepts about DNA

• The DNA double helix is a spiral ladder.
• The backbone is comprised of alternating deoxyribose and phosphate groups.
• Complementary pairs of bases (A-T, G-C) form the rungs of the DNA ladder.
• The DNA double helix is antiparallel.
• DNA coils tightly around histone proteins to form nucleosomes.
• Nucleosomes pack together to form chromatin.
• DNA replication is semi-conservative.

DNA, RNA, and Protein Synthesis

• A diagram showcasing DNA, RNA synthesis, and protein synthesis.
• Includes descriptions of DNA replication, DNA repair, genetic recombination, RNA synthesis, and protein synthesis.

The Process of Transcription

• The process of transcription has 3 stages: initiation, elongation, and termination.
• Many identical copies of RNA are produced simultaneously.

Types of RNA

• There are three major types of RNA: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).

Messenger RNA (mRNA)

• mRNA carries genetic information for a particular protein product.
• Three mRNA bases (codon) specify a particular amino acid.
• Specialized cells carry out specific functions due to the expression of particular mRNAs.

Ribosomal RNA (rRNA)

• rRNA associates with proteins to form ribosomes.
• Ribosomes are crucial for protein synthesis.
• Ribosomes are in two subunits in the cytoplasm, but combine for protein synthesis.

Transfer RNA (tRNA)

• tRNA is an adaptor molecule.
• tRNA matches amino acids to codons in mRNA.
• tRNA has a CCA sequence, crucial for amino acid attachment.
• tRNA contains an anticodon that binds to the complementary mRNA codon.

Amino Acid Table

• A table showing the relationship between codons and amino acids is presented.

Membrane Associated Proteins

• Membrane associated proteins have key roles, including transporters, anchors, receptors, and enzymes.

Regulation of Haematopoiesis

• A diagram illustrating the levels of regulation involved in RNA production including control of DNA sequences and the control of protein activities.

Bone Anatomy

• A diagram describing spongy bone (red marrow), compact bone, blood vessels, fat cells, bone, red blood cells, white blood cells, and platelets is shown.

Haematopoiesis

• 2.3 million new red blood cells are produced every second.
• 138 million red blood cells are produced every minute.
• Haematopoiesis produces 2 x 10^11 red blood cells daily and 1.45 x 10^15 in 20 years.
• A diagram illustrating haematopoiesis from hematopoetic stem cells to red blood cells.

Schematic Representations of Haematopoiesis

• Two diagrams (A and B) show different models of haematopoiesis.
• A illustrates a classic model with irrevocable pathway choices.
• B represents a pairwise model with developmental relationships biasing cells towards specific types.

Alternative Routes to Neutrophils and Monocytes

• Diagram illustrates alternative pathways for cell differentiation.

Haematopoietic Growth Factors

• A diagram is presented showing multipotent stem cell lineages, committed precursor cells, and lineage committed cells.

Production and Regulation of Haematopoietic Growth Factors

• A diagram illustrates the production and regulation of various factors involved in haematopoiesis, including erythropoietin, thrombopoietin, and G-CSF. Location is also noted.

Colony Forming Cell Assays

• A diagram shows how colony forming cell assays for human hematopoietic progenitor cells are done.

Types of Haematopoietic Colonies

• A graphic shows different types of Haematopoietic Colonies (CFU-E, CFU-M, BFU-E, CFU-GM, CFU-G, CFU-GEMM).

Red Blood Cells

• Red blood cells are depicted in different forms; as they appear on a blood film and in stylized forms to illustrate their structure.

Red Blood Cell Maturation

• A graphic describes the various stages of red blood cell maturation (from stem cell to RBC), marking important events at each stage.

What is EPO?

• EPO is essential for red blood cell production.
• EPO is regulated through blood oxygen levels.
• A diagram shows how imbalances in blood oxygen levels trigger EPO release from the kidney.

What is EPO? - Recombinant EPO

• Human recombinant EPO was cloned/expressed in 1985.
• Recombinant EPO (r-hEPO) is used clinically to treat certain types of anemia.

What is EPO? - An alternative therapy

• EPO has several additional benefits beyond anemia treatment, including neuroprotection, cardioprotection, retinal protection, wound healing, angiogenesis, and vascular protection.

Recombinant Erythropoietin (Aranesp)

• Aranesp and other treatments use darbepoetin alfa to treat anemia.

Blood Doping

• A diagram illustrating the process of blood doping is shown.

Oxygen Transport

• Oxygen and carbon dioxide exchange at the alveoli in the lungs is illustrated in a graphic.

A Tale of Two Proteins

• Haemoglobin and myoglobin are described as oxygen-carrying proteins.
• Haemoglobin carries oxygen throughout the body.
• Myoglobin stores oxygen primarily in muscle tissue.

Oxygen Binding and Unloading

• A diagram illustrating the process of oxygen binding to and unloading from haemoglobin.

Haemoglobin Chains

• A diagram of the primary, secondary, tertiary, and quaternary structures of haemoglobin.

Summary

• Haematopoiesis is the process of making mature blood cells.
• Specific growth factors regulate the development of blood cells.
• Erythropoietin (EPO) plays a crucial role in red blood cell production.
• The structure of haemoglobin is essential for its role in oxygen transport.

This quiz covers key concepts related to the structure and function of cells, including biomolecules like DNA and proteins, the process of haematopoiesis, and the roles of cytokines and hormones. Additionally, it explores the cell cycle and organelles, providing a comprehensive overview of cellular biology.