L01: Cellular organisation Flashcards
Whart are the levels or cellular organisation from smallest to largest?
Atoms, moleucles, cells, tissues, organs, organ systems, organism
What is the central dogma of molecular biology?
It is the flow of genetic information from DNA to RNA to proteins.
Describe the role of the nucleus in a cell.
The nucleus contains chromatine threads which store genetic information and instructions for protein synthesis. It is the side of DNA replication and mRNA synthesis.
What is the function of free and attached ribosomes?
Free ribosomes: Synthesize proteins used within the cytoplasm.
Bound ribosomes: synthesis of proteins that will be secreted outside the cell.
What in the function of the Rought Endoplasmic Reticulum? (RER)
The RER is involved in protein synthesis and transport, producing membrane bound and secretory proteins.
What is the function of the Smooth Endoplasmic Reticulum (SER)?
The SER lacks ribosomes and is involved in synthesis of proteins and lipids (Cholesterols) that is important in maintaining fluidity of cell membrane.
How does the Golgi Complex function within the cell?
It modifies, sorts, packages proteins and lipids received from RER for the transport or secretion. It invaginates the proteins in vesicles (secretory/transport) and they bud off to travel to their respective locations.
What is the role of lysosomes in cellular defense?
Lysosomes contain hydrolytic enzymes that phagocytose pathogens and digest damaged cell components. The lysosome is a phagosome. It helps break down cell components if necessary.
Explain how transport vesicles and secretory vesicles differ?
Transport vesicles: Helps transport substances within the cell.
Secretory Vesicle: Help carry materials outside the cell.
What role do peroxisomes play in cells?
Peroxisomes break down fatty acids and amino acids, producing hydroxide which is then broken by catalase to form water and oxygen.
Why is the mitochondria called the powerhouse of the cell?
It is the site of cellular respiration, where ATP is synthesized for cellular functions.
What are centrosomes and their role in cell division?
Centrosomes are made of two centrioles that help organize microtubules during cell division. They play a role in metaphase and anaphase.
Describe the stucture of the plasma membrane.
The plasma membrane is a phospholipid bilayer containing a hydrophobic tail and hydrophilic head. It is embedded with proteins and is selectively permeable.
At a molecular level, what causes sickle cell anemia?
A mutation caused by the change in nucleotide sequence that alters the hemoglobin protein, affecting its shape and function.
How can gene therapy potentially treat sickle cell anemia?
By adding normal genes to the bone marrow stem cells, gene therapy aims to produce functional hemoglobin.
