Life Science MCT Review

1. Life Science MCT Review

2. Genetics • Genesare small sections of DNA on a chromosomes that has information about a trait • Each chromosome has a gene for the same trait (eye color from mom & eye color from dad) • Traits are determined by alleles on the chromosomes • Each gene of a gene pair is called an allele • Inherited traits are determined by the alleles on the chromosome

3. The DNA Code • Chromosomes are made of DNA. • Each chromosome contains thousands of genes. • The sequence of bases in a gene forms a code that tells the cell what protein to produce.

4. Types of Alleles • Dominant Alleles describe a genetic factor that is always expressed. • Represented by capital letters (B) • RecessiveAlleles- onlyexpresses itself when both of the recessive traits are inherited • Represented by lowercase letters (b)

5. Examining & Studying Traits • Two ways scientist study traits • Phenotype: outside expression of a gene • Blue Eyes • Genotype: the two alleles a person has inherited that can only be seen on the DNA • BB, Bb, or bb • Two categories of genotypes • Homozygous: inherited two identical alleles • BB (pure dominant) or bb (pure recessive) • Heterozygous: inherited two different alleles • Bb (hybrid)

6. Punnett Squares Mom • Shows all possible combinations of alleles that children can inherit from parents • Mom’s genotype for brown eyes (Bb) • Dad’s genotype for brown eyes (Bb) • Offspring’s Phenotype • 75% brown, 25% blue • Offspring’s Genotype • 25% BB, 50% Bb, 25% bb Dad brown brown brown blue

7. Punnett Square Practice • What is the genotype and the phenotype for each parent? • What are the possible genotypes and the phenotypes for the offspring?

8. Codominance • In codominance, the alleles are neither dominant nor recessive. As a result, both alleles are expressed in the offspring. • FW FB = black & white • FB FB = black • FW FW = white

9. Incomplete Dominance • In incomplete dominance, one allele is not completely dominant over the other allele . As a result, both alleles have a blended expression. • RR = red • WW = white • RW = pink

10. A Hemophilia Pedigree (Sex-linked) • The chart below follows hemophilia in a family. Hemophilia is a genetic disorder that does not allow the blood to clot normally. How many males have hemophilia?

11. Selective Breeding • Selective Breeding is an intentional mating of organisms to produce offspring with specific traits • Examples: breeding dogs, making new forms of fruits or vegetables

12. Genetic Engineering • Genetic engineering changes the genetic material of a living organism by removing genes from one organism then transferring them into the DNA of another organism. • Uses: • Make medication and treat diseases • cure human genetic disorders • Improve crops • Ex. Insert bacteria DNA into rice, wheat, and tomatoes to enable plants to survive in colder temperatures and resist insects.

13. Gene Therapy • Gene therapy is an experimental technique that uses genes to treat or prevent disease by inserting working copies of a gene directly into the cells of a person with a genetic disorder • Researchers are testing several approaches to gene therapy, including: • Replacing a mutated gene that causes disease with a healthy copy of the gene. • Inactivating, or “knocking out,” a mutated gene that is functioning improperly. • Introducing a new gene into the body to help fight a disease. • Several studies have already shown that this approach can have very serious health risks, such as toxicity, inflammation, and cancer.

14. Adaptations, Biomes, & Ecology Obj. 3a, 3e, &3h

15. Adaptations to an Environment • An adaptation is a trait that an organism has inherited that helps them survive and reproduce in their habitat • Ex. Sharks sense of smell, shape of a bird’s beak, dogs can hear well, flowers have bright colors • Physical adaptations do not develop during one lifetime, but over manygenerations

16. Adaptation over time • Natural selection is the process by which individuals who are better adapted to their environment are more likely to survive and reproduce than other members of the same species. • Caused by variations among individuals.

17. Biomes

18. Adaptations to Taiga • Dominant plants adapt with needle-shaped leaves to reduce water loss by having less surface area • Ex. evergreens • Animal have adapted by camouflage, hibernating or migrating, & thick fur

19. Adaptations to Rainforests • Plant & animal life adapts in a variety of ways • Camouflage • Poisonous • Large leaves

20. Adaptations to Deserts • Plants- thick stems, needles, deep roots • Animals- camouflage, hibernation, hiding under rocks

21. Ecology

22. Populations All the organisms in an ecosystem that belong to the same species Ex. Mice living in a meadow or pine trees in a forest

23. Community All the populations of different species that live in an ecosystem & share resources Ex. Pine tree forest forms a community with populations of deer, mice, raccoons, bacteria, mushrooms, & ferns

24. Photosynthesis • Plants use carbon dioxide and hydrogen with light-energy in the presence of chlorophyll in the chloroplast of the cells to make glucose and oxygen • Directly or indirectly produces food for almost all organisms • Algae are producers for the ocean. carbon dioxide + water + sunlight oxygen + glucose (CO2) (H2O) (energy) (O2) (C6H1206)

25. Cellular Respiration • The purpose of cellular respirations is to release energy that can be used by cells to perform their specialized function • Cellular respiration occurs in the mitochondria of cells. oxygen + sugar carbon dioxide + water + energy (O2) (C6H1206) (CO2) (H2O)

26. Food Webs • A model that links the organisms within an ecosystem by how they depend on each other for food. • The lines drawn represent the flow of energy through the ecosystem & show a variety of food chains

27. Energy Pyramid • Anenergy pyramid shows the relative amount of energy available at each trophic level. • Organisms use about 10% of this energy for life processes. The rest is lost as heat.

28. Energy Pyramid

29. Types of Cells

30. Cell Wall • Rigid layer that surrounds the cells of plants and some other organisms • It helps protect and support.

31. Cell Membrane • The cell membrane protects the contents of the cell and helps control the materials that enter and leave. • Allows food and oxygen into the cell and waste products out of the cell.

32. Chloroplast • Green structures typically found in plant cell to make food by photosynthesis. • Captures energy from sun-light and changes it to energy the cell needs to make food. O₂ Glucose

33. Vacuole • Type of sac that stores water, food, and other materials needed by the cell. • Vacuoles in plants cell are larger than those in animal cells. Vacuole

34. Comparing Plant and Animal Cells • Plant cells have a largervacuole for more storage. • Plants have chloroplasts for carrying out photosynthesis. • Plants have cell walls for shape & support.

35. Epithelial Tissue • Tissue that covers internal or external surfaces of an animal’s body • Cells are packed tightly together with little space between. • Examples: skin, linings of internal organs, blood vessels

36. Blood • Tissue that carries oxygen, nutrients, removes wastes, and fights infection.

37. Bone • A rigid connective tissue made mostly of calcium. • Provides shape and support, protection, and allow the body to move.

38. Adipose Tissue • A loose connective tissue also called fat. • Stores energy, cushions and insulates the body. • Found beneath the skin and around internal organs.

39. Muscle Tissue • Tissues that contract and relax to allow the body to move.

40. Nervous Tissue • Neurons (nerve cells) are the basic unit of the nervous system. • Form the brain, spinal cord, and other nerves. • Controls the body and responds to stimuli.

41. How Tissues Work Together

42. Diseases Caused By Cells • Infectiousdiseases are caused by a microorganism that is transmitted or spread from one organism to another. • A pathogen is any microorganism that causes a disease • Types of pathogens: • Viruses • Bacteria • Protists • Fungi

43. Pathogens STREP ATHLETE’S FOOT INFLUENZA EBOLA

44. Virus • A tiny non-living particle made of nucleic acid (genetic material) covered with a protein coating that can only reproduce inside of a living cell (host) • The host provides the energy for the virusuntil it is destroyed by the virus.

45. Types of Viruses • Common Cold • HIV • Polio • Smallpox • Chickenpox • Yellow fever • Measles • Ebola • Influenza (Flu)

46. Virus Shapes

47. Treatment of Viruses • Vaccines can be used to prevent viruses. • A vaccine is a small dose of the weakened or inactive form of the virus that allows the immune system to fight the disease by creating antibodiesagainst the virus. • Many viruses have no cure.

48. Gene Therapy with Viruses • Because viruses are so small, they can be used to carry DNA inside a cell. • This can be used to treat some genetic diseases.

49. Common Viral Diseases • Unlike with bacterial diseases, there are currently no medications that can cure viral infections.

50. Bacteria • Bacteria are single-celled organisms that do not have a nucleus. • Have a cell wall.