BM: Proteins, Enzymes, ATP, Flashcards
Describe the differences between globular and fibrous proteins. Provide an example of each type of protein and explain their functions.
Globular proteins are compact and spherical, soluble in water, and often involved in biological processes. Example: Haemoglobin, which transports oxygen in the blood.
Fibrous proteins are long, thread-like structures, insoluble in water, and provide structural support. Example: Collagen, which strengthens tendons and ligaments.
Explain the role of haemoglobin in the transport of oxygen in the bloodstream.
Haemoglobin is a globular protein in red blood cells that binds to oxygen molecules. It transports oxygen from the lungs to tissues throughout the body. Its quaternary structure allows it to pick up oxygen in areas of high concentration and release it in areas of low concentration.
Identify the four levels of protein structure and describe the primary and secondary structures in detail, including their significance in protein function.
Primary structure: The sequence of amino acids in a polypeptide chain. It determines the protein’s unique characteristics.
Secondary structure: The folding of the polypeptide into structures like alpha helices or beta sheets, stabilized by hydrogen bonds. This determines the protein’s shape and function.
Explain how disulfide bridges contribute to the stability of proteins under extreme conditions such as changes in pH or temperature.
Disulfide bridges are covalent bonds formed between sulfur atoms in cysteine residues. They provide additional strength and stability to the protein’s tertiary structure, helping it maintain its shape even under harsh conditions like extreme pH or temperature changes.
Describe the functions of fibrous proteins in the human body, providing two examples and their roles in tissues and structures.
Fibrous proteins have a supportive role and provide structural strength.
Collagen: Found in tendons, ligaments, and skin, providing strength and flexibility.
Keratin: Found in hair, nails, and the outer layer of skin, providing rigidity and protection.
Describe the structural differences between DNA and RNA, and explain their respective functions in cellular processes.
DNA: Double-stranded helix, contains deoxyribose sugar, and stores genetic information.
RNA: Single-stranded, contains ribose sugar, and is involved in protein synthesis by carrying genetic instructions from DNA to the ribosomes.
Explain the process of DNA replication, highlighting the roles of helicase and DNA polymerase in ensuring accurate copying of the genetic material.
Helicase unwinds the double helix, separating the two DNA strands.
DNA polymerase adds complementary nucleotides to each strand, ensuring the creation of two identical DNA molecules. The process is highly accurate due to proofreading by DNA polymerase.
Identify the role of mRNA in protein synthesis and describe the steps involved in translating mRNA into a polypeptide chain at the ribosome.
mRNA: It carries the genetic code from DNA in the nucleus to the ribosomes in the cytoplasm.
Translation: mRNA is read in sets of three nucleotides (codons), each coding for an amino acid. tRNA brings amino acids to the ribosome, where they are linked to form a polypeptide chain that folds into a functional protein.
Explain the concept of degeneracy in the genetic code and how this property helps minimize the effects of mutations.
Degeneracy refers to the redundancy in the genetic code where multiple codons can code for the same amino acid. This minimizes the impact of mutations because a change in one nucleotide may still result in the same amino acid being produced.
Describe the importance of complementary base pairing during DNA replication, and explain how this mechanism ensures fidelity in the replication process.
Complementary base pairing ensures that adenine always pairs with thymine, and guanine pairs with cytosine. This accurate pairing between the strands of DNA helps preserve the integrity of the genetic code during replication.
Describe the structure of ATP and explain why it is considered the primary energy carrier in cells.
ATP consists of three phosphate groups, adenine (a nitrogenous base), and ribose (a sugar). It is considered the primary energy carrier because its high-energy phosphate bonds release energy when broken, which cells use for various metabolic processes.
Explain the process of ATP hydrolysis and discuss its significance in cellular metabolism and energy transfer.
ATP hydrolysis involves the breakdown of ATP into ADP and a free phosphate group, releasing energy. This energy is used for cellular processes like muscle contraction, active transport, and protein synthesis.
Compare aerobic and anaerobic respiration in terms of ATP production, and explain the conditions under which each process occurs.
Aerobic respiration requires oxygen and produces a large amount of ATP (approximately 36 ATP molecules per glucose molecule) in the mitochondria.
Anaerobic respiration occurs in the absence of oxygen and produces much less ATP (2 ATP molecules per glucose molecule), typically in the cytoplasm.
Explain how ATP is used in active transport across cell membranes and its importance in maintaining cellular homeostasis.
ATP powers transport proteins in the plasma membrane, moving substances against their concentration gradients. This is crucial for maintaining cellular homeostasis by ensuring the proper balance of ions and nutrients inside the cell.
Describe the role of ATP in muscle contraction, and explain how energy is transferred during this process.
ATP provides the energy for muscle contractions by binding to myosin, causing it to change shape and pull on actin filaments. This transfer of energy allows the muscle fibers to shorten and produce movement.
