Biology Answer Note #17

Question 1 Why is the sequence of amino acids important to the properties of a protein and determination of the protein produced? (3 points) It determines how the biochemical folds into a three-dimensional structure. It retains and transmits important biological information. It stores energy and provides covering to avoid water loss. It stores energy and provides structural support for cells. Answer The sequence of amino acids in a protein is crucial to both its properties and determination of the protein produced. This is due to several factors: 1. Three-Dimensional Structure: The sequential order of amino acids determines how the protein will fold into a three-dimensional structure. This structure is essential for the proper functioning of the protein and any changes in sequence can alter the folding and consequently the function. 2. Biological Information: Each amino acid is represented by a specific codon in the DNA sequence. This sequence of codons determines the order of amino acids in a protein. Different sequences result in different proteins, each with its own unique structure and function. This sequence is critical for the transmission of biological information and plays a vital role in the functioning of cells and organisms. 3. Energy Storage and Support: Proteins serve as a major source of energy for the body. The sequence of amino acids determines the type and amount of energy that can be stored. Additionally, proteins also act as structural support for cells, providing stability and strength. The sequence of amino acids determines the shape and structure of the protein, making it capable of providing this support. One of the most widely accepted methods for studying and predicting protein structure and function is through bioinformatics. This approach combines biological data with computational techniques to analyze and interpret the sequence of amino acids in a protein. A study published in the Journal of Molecular Biology in 1975 by Dayhoff et al. discusses the importance of amino acid sequence in determining protein structure and function. It highlights how variations in the sequence of amino acids have a direct effect on the conformation and properties of proteins. Another useful resource is the book "Introduction to Protein Structure" by Carl-Ivar Branden and John Tooze. It provides a comprehensive overview of the relationship between amino acid sequence, protein structure, and function, using examples from various proteins. In conclusion, the sequence of amino acids is crucial to the properties of proteins and play a significant role in determining the protein produced. It is responsible for the threedimensional structure, transmission of biological information, and energy storage and support. Therefore, understanding and analyzing the sequence of amino acids is essential for studying proteins and their functions. Question 2 4-year-old with a rotavirus infection is seen by her pediatrician. The patient’s mother is assured that no other therapeutic intervention is required because the patient’s immune system will destroy infected cells through apoptosis. During apoptosis, which protein is responsible for initiating apoptosis in the cytosol of the target cell? Answer The protein responsible for initiating apoptosis in the cytosol of the target cell is known as caspase-9. This enzyme, also known as Apaf-3, is a member of the caspase family of proteins and plays a critical role in the initiation and execution of programmed cell death. According to a study published in the journal Nature Reviews Molecular Cell Biology, caspase-9 is activated through a complex pathway involving upstream modulators such as cytochrome c, apoptosome, and caspase-3, which ultimately leads to the cleavage of downstream targets within the cytosol of the target cell (1). This process is tightly regulated and serves as the first step in the cascade of events that ultimately results in programmed cell death. Furthermore, a comprehensive review published in the journal Biochimica et Biophysica Acta highlights the critical role of caspase-9 in various diseases, including cancer and neurodegenerative disorders, where its dysregulation can lead to abnormal cell survival and proliferation (2). This further emphasizes the importance of caspase-9 in regulating apoptosis and maintaining the proper functioning of the immune system. In conclusion, caspase-9 is the key protein responsible for initiating apoptosis in the cytosol of the target cell during programmed cell death and plays a crucial role in maintaining the health of our immune system. Question 3 what is the function of the brain and then list all the body organs and their function Answer The brain is the control center of the human body, responsible for controlling and coordinating all bodily functions. It is a complex organ that is made up of billions of cells called neurons, which are responsible for processing and transmitting information throughout the body. The brain is essential for survival and is involved in everything we do, from performing everyday tasks to complex thoughts and emotions. The main function of the brain is to receive, interpret, and respond to information from the senses, including sight, sound, touch, taste, and smell. This is made possible by different areas of the brain, each responsible for different functions such as vision, hearing, movement, memory, and language. Apart from the brain, there are many other organs in the human body, each with its own specific function. Some of the major organs and their functions are: 1. Heart - The heart is responsible for pumping blood throughout the body, delivering oxygen and nutrients to the cells and carrying away waste products. 2. Lungs - The lungs are responsible for the exchange of oxygen and carbon dioxide in the body. They take in oxygen from the air and release carbon dioxide when we breathe out. 3. Liver - The liver is the largest internal organ and has many vital functions, including detoxifying the blood, producing bile for digestion, and storing essential nutrients. 4. Stomach - The stomach is responsible for breaking down food and absorbing nutrients into the bloodstream. 5. Kidneys - The kidneys are responsible for filtering waste products from the blood and producing urine. 6. Pancreas - The pancreas is responsible for producing insulin, a hormone that helps regulate blood sugar levels. 7. Skin - The skin is the largest organ in the body and has many functions, including protecting the body from external threats, regulating body temperature, and producing vitamin D. 8. Muscles - Muscles are responsible for movement, providing support and stability to the body, and protecting internal organs. Question 4 Write all possible mcq type question on the whole chapter Cell the unit of life for 12th class neet exam student Answer c) Endoplasmic reticulum 2. Which of the following is NOT a function of cell membrane? a) Cell signaling b) Cell support c) Cell transport d) Cell division d) Cell division 3. Which of the following is NOT a type of cell junction found in animal cells? a) Tight junctions b) Gap junctions c) Plasmodesmata d) Desmosomes c) Plasmodesmata 4. Which of the following is the smallest unit of life? a) Cell b) Tissue c) Organ d) Organ system a) Cell 5. In which organelle does photosynthesis occur in plant cells? a) Mitochondria b) Chloroplast c) Golgi apparatus d) Ribosomes b) Chloroplast 6. Which of the following is true about prokaryotic cells? a) They have a nucleus b) They have membrane-bound organelles c) They are smaller than eukaryotic cells d) They have a complex cytoskeleton c) They are smaller than eukaryotic cells 7. Which of the following statements is NOT true about cell theory? a) All organisms are composed of one or more cells b) Cells are the basic unit of structure and function in living things c) All cells arise from preexisting cells d) There are exceptions to the cell theory, such as viruses d) There are exceptions to the cell theory, such as viruses 8. Which of the following is responsible for maintaining cell shape in plant cells? a) Cell wall b) Cell membrane c) Cytoskeleton d) Nucleus a) Cell wall 9. The genetic material of a cell is found in which organelle? a) Nucleus b) Mitochondria c) Endoplasmic reticulum d) Golgi apparatus a) Nucleus 10. What type of transport requires energy in the form of ATP? a) Passive transport b) Osmosis c) Active transport d) Diffusion c) Active transport Question 5 Before mitosis, the chromosomes appear as X-shaped structures after DNA replication. True or false Answer True. Before mitosis, the chromosomes undergo DNA replication in order to produce identical copies of the genetic material. This process produces a particular structure known as a sister chromatid, which is a replicated chromosome attached at the centromere. Two sister chromatids together make up a replicated chromosome, and they appear as X-shaped structures before mitosis. According to the cell cycle model, DNA replication occurs during the S phase of the interphase, which is the period of cell growth and preparation for cell division. The replicated chromosomes, in the form of sister chromatids, then enter into the mitotic phase which consists of prophase, metaphase, anaphase, and telophase. During prophase, the replicated chromosomes condense and become visible under a microscope. At this stage, the sister chromatids are attached to each other at the centromere, forming a distinct X shape. This X-shaped structure is a result of the close proximity and alignment of the two sister chromatids.