SNC2D - Grade 10 Science Essays - Biology, Anatomy, Cell Biology

SNC2D - Grade 10 Science Unit Test Review Key Cells, Tissues and Living Systems Plant and Animal Cells, Cell Theory, Cell Structure (p. 29, 30-32) The cell theory states that: Every living organism is made of one or more cells. The cell is the basic unit of structure and function. It is the smallest unit that can perform life functions. All cells arise from pre-existing cells. 2. How are prokaryotic cells different from eukaryotic cells? Give one example of each. Prokaryotic cells lack a true nucleus and do not have membrane-bound organelles. Example of a prokaryote: bacteriaExample of a eukaryote: plant or animal cell 46990096520 7. endoplasmic reticulum 2.Golgi body cytoplasm 3.mitochondria00 7. endoplasmic reticulum 2.Golgi body cytoplasm 3.mitochondriaLabel the parts of the animal cell. 41275016891000 3886200127635 4. vacuole/lysosome00 4. vacuole/lysosome -15240095250 8.(dots) ribosome00 8.(dots) ribosome 3962400-1905 5. nucleus00 5. nucleus 388620043815 6.nuclear membrane00 6.nuclear membrane Referring to question 3, list the numbered parts of the animal cell and fill in their respective functions in the table below: Cell Structure Function 1. Cytoplasm consists of organelles, molecules, ions and water 2. Golgi body involved with packaging and secretion of proteins 3. Mitochondrion Site where energy for the cell is produced It is also referred to as the "power house" of the cell 3. Lysosomes /vacuoles contain digestive chemicals called enzymes may contain cell debris or chemicals 5. Nucleus the control centre of the cell; contains the genetic material (DNA) of the cell Nuclear membrane Regulates movement of substances into and out of the nucleus 7. E ndoplasmic reticulum Network for the transport of substances throughout the cell 8. Ribosomes involved with making proteins -36893553975 1. chloroplast 3. vacuole 00 1. chloroplast 3. vacuole Label the numbered parts of the plant cell. -69215178435 2. cell wall00 2. cell wall By referring to question 5, list the numbered parts of the plant cell and fill in their respective functions in the table below: Cell Structure Function chloroplast Where photosynthesis happens cell wall Provides rigidity to the plant vacuole keeps the cells plump which keeps the plant's stems and leaves firm. 8. Name three differences between plant and animal cells. Plant cells have (1) a cell wall, (2) chloroplasts for photosynthesis, and (3) 1 large vacuole(animal cells have multiple, smaller, vacuoles) Cell Division, Cell Cycle (pp. 36-37, 40-43) 396240043180001. Refer to the diagrams below for question 3. 2286006477000 2514600132715 C00 C 22098004000500 426720015240 D00 D 30480083185 A00 A 45720003683000 -15240010477500 24384005842000 3886200101600 E00 E 99060055245 B00 B 5105400123190 F00 F Which of the following diagrams (A-F) shows: 1447800112395 F00 F09906000 137160010160 A00 A 137160078105 D00 D 1371600155575 C00 C 13716006985 B00 B 140017584455 E00 E 2. Why don't cells grow indefinitely? Cells are limited in size because the outside (the cell membrane) must transport the food and oxygen to the parts inside. As a cell gets bigger, the outside is unable to keep up with the inside, and the cell membrane cannot supply the inside with what it needs to survive. Diffusion of nutrients throughout the cell also takes longer. What are 3 purposes of cell division? Growth (2) Reproduction (3) Repair What purpose does mitosis serve in the cell cycle? Equal distribution of genetic material between the two daughter cells Equal distribution of the cytoplasm and organelles between the two daughter cells (cytokinesis) Compare contrast diffusion and osmosis. Diffusion - movement of the solute from an area of high solute concentration to low concentration Osmosis - movement of water towards an area of high solute concentration Compare - both water and the solute move from areas of high concentration (water or solute) to low concentration Cancer (pp. 48-55) Define metastasis. When some of the cancerous cells break off from the primary tumour , spread through the blood and lymph and establish a secondary tumour in a new location. Describe the steps for a secondary tumour formation. Step 1: The primary tumour develops as a group of cells that are undergoing uncontrolled cell division Step 2: As the tumour gets bigger, it stimulates blood vessels to form and supply it with nutrients. Step 3: Tumour cells enter blood vessels and lymph vessels. This is dangerous because the tumour cells can move to other parts of body (metastasis). Step 4: Primary cells which arrive at new area of the body form secondary tumour s , which may eventually be fatal to the organism. How does a doctor diagnose cancer once he or she has located a tumour ? Biopsy (tissue sample) What are some reasons why cancer might recur after it has been successfully removed from a person? After surgery, a vast amount of the primary tumour is removed . H owever,

Sex Education in schools essays

Sex Education in schools essays The good news is that the teen pregnancy rate in the U.S. is the lowest its been since the early 70's, primarily due to teens increased and improved use of birth control. The bad news is that one million U.S. teens still get pregnant each year, and 78 percent of those pregnancies are unintended. The fact is that most young people in the United States begin having sex in their teens and they need honest and straightforward information about sex in order to protect themselves from unintended pregnancy. Obvious, right? Well apparently not to President Bush, who asked Congress for a 33% increase in funding for abstinence-only sex education, which would forbid teachers to talk about how contraception works or where to get it. Abstinence-only programs keep teens in the dark about sex; they have not been proven to delay or reduce sexual activity; and they fail to provide accurate information about preventing pregnancy and disease. Comprehensive sexuality education, on the other hand, teaches that sexuality is healthy, normal part of human being. It teaches students about the advantages of abstinence, while also giving them the realistic information they need about the prevention of unintended pregnancy and sexually transmitted infections. Studies show that balanced programs that promote both abstinence and safer sex are most effective and allow young people to make responsible choices. In California, teen birth rate has dropped more than 40 percent over the last decade. The credit goes to a state-sponsored program that provides information on sexual abstinence and birth control. Teen birth rate has fallen from 11th nationwide in 1991 to 21st in 2002, according to the California Wellness Foundation. California is the only state that refuses to accept federal sex-education money, which requires public schools to teach only sexual abstinence and avoid providing information on contraception ...