Bio-Pac 02: Objective 05 and 07-12 Flashcards
Objective 5. Explain the function of the following parts of a cell: plastids, microtubules, spindle fibers, cilia, flagella, lysosomes, vacuoles, mitochondria, ribosomes, endoplasmic reticulum, Golgi bodies, cytoplasm, cell membrane, and cell wall.
The function of a plastid is that they are plant organelles that are used to store energy. The chlorophyll in the chloroplasts is used to trap the light, and then the chloroplast will change the light into usable chemical energy. The plastid then takes that usable chemical energy and stores it in itself, so the usable chemical energy is then stored in food molecules (plastid). The function of microtubules is that they are thin, hollow cylinders made of proteins that make up the cytoskeleton which supports the organelles in the cytoplasm. Microtubules are the thin hollow cylinders of fibrous elements made of proteins that make up the cytoskeleton which supports the organelles in the cytoplasm. The function of spindle fibers which are foot-ball-shaped, cage like structures consisting of thin fibers made of microtubules is to separate the chromatids during mitosis. The function of cilia is to move a cell or to move fluids over the cell’s surface. The function of flagella is to move the cell by moving the tail in a whip like motion. The function of vacuoles is to store food, enzymes, and other materials needed by a cell as well as waste products before they can exit the cell. The function of the mitochondria is to break down food molecules (cellular respiration) so energy is then released so it can power cell reactions, and they are used to produce energy-storing molecules. The function of ribosomes is to produce enzymes and proteins (protein synthesis). The function of an endoplasmic reticulum is to let many chemical reactions occur within it because it has so much surface area, and it is used as a transport system for materials throughout the cell. The function of Golgi Bodies is to receive newly synthesized proteins and lipids from the endoplasmic reticulum and then to repackage them so they can be used by the plasma membrane and organelles, once they are repackaged from what the endoplasmic reticulum packaged them in then they are transported to the cell membrane and organelles, another function is to create lysosomes, secretions (hormones) them so they can be distributed them to the plasma membrane and other organelles. The function of cytoplasm is to contain the organelles and the cytoskeleton which holds the organelles in place, and also to allow chemical reactions to occur within it. The function of the cell membrane is to serve as the boundary line between the cell and its external environment; it also controls things going in and out of the cell (selectively permeable). The function of the cell wall is give an additional boundary between the cell and its environment, and because it is inflexible because it is made of cellulose fibers that are woven together to make a strong network of cellulose fibers (network is called the cell wall) the cell wall supports the cell and gives it protection.
Objective 7. Design a chart to compare prokaryotes and eukaryotes for the following items: nuclear membrane, chromosomes, chlorophyll, and cytoplasm.
Nuclear Membrane
Prokaryote: No nucleus so no nuclear membrane
Eukaryote: Has a nucleus membrane so there is a nuclear membrane. The nuclear membrane has large pores that allow materials to pass back and forth between the nucleus and the rest of the cell. It is a double membrane structure, and each membrane is two layers thick. Also called nuclear envelope.
Chromosomes
Prokaryote: Circular DNA in the cytoplasm
Eukaryote: Long DNA containing many noncoding regions; organized into chromosomes and bounded by nuclear envelope.
Chlorophyll
Prokaryote: Most of the times it is not present but sometimes it is, and if it is scattered in cytoplasm.
Eukaryote: Present in plant cells but not present in animal cells.
Cytoplasm
Prokaryote: No cytoskeleton, no cytoplasmic streaming, no endocytosis (transport of matter into a cell by means of a vacuole), and no exocytosis (transport of material out of a cell).
Eukaryote: Cytoskeleton composed of protein filaments, cytoplasmic streaming, endocytosis (transport of matter into a cell by means of a vacuole), and exocytosis (transport of material out of a cell).
Objective 8. Describe cellular organization as it applies to multicellular organisms.
Single celled organisms need to do all processes themselves to stay alive, because they only rely on themself. Multicellular organisms have the cells work together, meaning that each cell has a specialized metabolic function, and do not carry out all life functions but depend on each other to keep the organism alive. The organization of multicellular organism goes from a group of cells that function together to perform one activity-tissue, then to groups of two or more tissues that function together-organs, then when the organs cooperate with each other to carry out major life functions-organ system.
Objective 9. Differentiate between the cell wall of a plant cell and that of a bacteria cell.
The cell wall of a plant and the cell wall of a bacteria cell are different. The cell wall of a plant cell is inflexible and is made of cellulose fibers woven together to form a strong, inflexible, supporting, and protecting network of fibers for the cell. It also serves as a boundary between the cell and its environment. The cell wall of bacteria is different though. It is a rigid covering for the cell that is made of long sugar chains and short amino acid chains. The function of the cell wall in bacteria is to prevent osmotic rupture. This is because most bacteria live in a hypotonic environment, meaning there is a high concentration of water. Because of this, the bacteria cell needs a cell wall to prevent water from coming in uncontrollably because a cell needs to control how much water comes into it because it needs water, but if too much comes in uncontrollably because of osmotic rupture the cell will die.
Objective 10. Explain why scientists do not believe viruses to be “living.”
Scientists believe that viruses are not living. Diseases are not caused by bacteria and not by organisms but by viruses, however diseases can also be caused by bacteriophage which is virus infected bacteria. Viruses are about half to a hundredth the size of the smallest bacterium. They are not considered living like prokaryotes and eukaryotes but they are considered nonliving, because they do not meet the criteria for being alive. For example they do not carry out respiration, grow, or move, but can only reproduce. Even when they reproduce they can’t do it by themselves, but must be with a host cell to reproduce.
Objective 11. Draw and label a typical bacteria cell.
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Objective 12. Describe the structure of a typical virus.
A virus consists of an inner core of nucleic acid surrounded by one or two protein coats, but if the virus is as large as the human flu virus then it may have another layer called the viral envelope which is made out of phospholipids that surrounds the other two protein coats. The nucleic acid which is the virus’s inner core contains the virus’s genetic material- DNA or RNA- it will either contain DNA or RNA in the nucleic acid but just one. It contains one because it only needs the code for making copies and nothing else. The arrangement of the proteins in the one or two protein coats gives the viruses different shapes.
