BIO113 Exam 2 Ch 4, 10, 13

Transcription

1 BIO113 Exam 2 Ch 4, 10, 13 See course outline for specific reading assignments Study notes and focus on terms and concepts The images in the textbook are useful

2 CELLS (pg. 37) The basic unit of life living things are composed of at least one cell cells metabolize (obtain energy, use energy, make waste) cells can reproduce cells sense and respond to the environment red blood cell brain cell sperm egg Some human cells

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4 Cells need a large surface area to volume ratio

5 3 parts of the eukaryotic cell Cheek epithelial cells

6 1. plasma (cell) membrane Selectively permeable Lipid bilayer hydrophilic outer/inner portions hydrophobic within

7 The membrane determines what can get into and out of the cell such as..

8 Fluid mosaic model Dynamic!

9 membrane proteins Transporters, Channels ferry substances Example: glucose transporters Example: chloride ion channel

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11 Cystic fibrosis (CF) and cell membrane most common serious genetic disease in the US A single gene mutation causes a cell membrane Cl- transport protein to malfunction

12 Cells produce thick, sticky mucus that clogs the lungs infections

13 2. DNA

14 Eukaryotic cells have a nucleus that contains DNA Why is DNA important? DNA in nucleus

15 DNA = instructions for cells to manufacture proteins DNA = genetic material

16 DNA is in the form of chromosomes 46 long strands of DNA per cell (23 in egg and sperm)

17 3. cytoplasm (fluid-like interior) Contains ORGANELLES

18 2 Organelles found in the cytoplasm of the eukaryotic cell 1. lysosomes Bags of enzymes that clean old parts, digest foreign matter

19 Microscopic view of affected brain Tay Sach s disease and lysosomes Mutation in a single gene results in a malfunctioning lysosomal enzyme Lysosomes fill up with lipid (fatty substance) Normal until ~ 1year, brain deteriorates, fatal ~age 3

20 Lysosomes and apoptosis Apoptosis = programmed cell death Ex. Tadpole tail, fingers during human embryonic development

21 2. mitochondria produce energy (ATP) use oxygen and fuel (sugar)

22 The human life cycle DNA has the instructions

23 These instructions are on chromosomes which contain units of information called genes

24 Gregor Mendel (~1850) the father of genetics Worked out the transmission of traits from parent to offspring using pea plants What makes peas good genetic subjects (compared to humans)?

25 Pisum sativum Single gene traits

26 Start with true-breeding varieties Cross or self pollination Keep detailed records Statistical analysis

27 1. Particulate theory of inheritance Modern version: Genes are physical units passed from parent to offspring

28 The monohybrid (one gene) cross

29 2. Principle of dominance : For each gene we have 2 alleles Dominant allele observed in phenotype (appearance) B = brown eye allele G = yellow pea allele

30 recessive allele is masked by a dominant allele b = blue eye allele g = green pea allele BUT, each individual has two alleles per gene. What are the 3 possible GENOTYPES?

31 Fill in for eye color Genotype Genotype Phenotype Homozygous dominant Homozygous Recessive Heterozygous

32 3. Principle of segregation Modern version: each sperm and egg randomly gets one allele per trait and fertilization gives the new individual 2 alleles per trait

33 Sickle cell disease S = normal allele s = sickle cell allele Mutation in the gene for hemoglobin Red blood cells form a sickle shape when oxygen is low

34 The sickled red blood cells cannot fit through capillaries Causes joint pain, anemia why? Over time stresses kidneys, heart, other organs An example of pleiotropy = single gene, multiple effects

35 Harmful recessive alleles: Bedouin intermarriage Bedoin intermarriage

36 Continuous variation results from many genes (polygenic) Examples:

37 Bell shaped curve shows continuous variation

38 IQ is polygenic

39 phenotype also affected by environment -Skin color melanin production increased by sun -Height is ~90% genetic

40 X-linked genes genes that are ONLY on the X chromosome Females have 2 allele Males have 1 allele

41 Other single gene disorders Hemophilia mutation in X-linked gene Lack of protein required for blood clotting

42 Use this notation ONLY for X-linked genes X H X H = X H Y = X H X h = X h Y = X h X h =

43 Chromosomes = strands of DNA in nucleus Gene = unit of information on a chromosome DNA = molecule that composes chromosomes/genes

44 Genes (and alleles) are located on chromosomes Humans have 46 chromosomes in each somatic cell nucleus Somatic cell = body cell (not sperm or egg) A human chromosome in nucleus

45 Chromosomes are copied before a cell divides into 2 cells so that each new cell has a full set

46 Humans have 2 sets of chromosomes in each cell 23 from egg 23 from sperm Fertilized egg

47 Homologous chromosomes Chromosomes of (most) animals are in pairs Homologues have same genes at same positions Each chromosome has 100s or 1000s of genes

48 Chromosomes and genetics Human 46 Chimpanzee 48 Dog 78 Cat 72 Alligator 32 Goldfish 94 Mosquito 6 Potato 48 Baker s yeast 34 The more complex the organism the more chromosomes?

49 Karyotype photo of chromosomes arranged according to? Pairs 1 through 22 = autosomes Sex chromosomes are X and Y Note the homologous pairs Cant see individual genes!

50 Fig Autosomes are the same in male and female The Y chromosome determines sex! What genes are on the Y? The X?

51 Look at the pairs, what is different about these two karyotypes? Female = XX Male = XY

52 Chromosomal number disorders 47, XX, 21+ Down syndrome Page 136 (ch 9)

53 Klinefelter syndrome Chromosomal notation?

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55 Chromosomal changes Translocation = portion of one chromosome another

56 C. Deletion small piece of a chromosome lost Example: Cri du Chat

57 D. Inversion a piece of a chromosome inverts (flips) 16 year old with leukemia (AML) Note this karyotype is from the cancerous cells only

58 Genetic testing 1. Of children and adults Obtain chromosomes/dna from cells for testing

59 2. Prenatal testing 1. ultrasound for fetal anatomy, age, size, twins Can pick up defects such as spina bifida

60 2. Fetal testing Test fetus in utero

61 A. amniocentesis Obtain fluid from sac via needle through uterus - contains fetal cells

62 B. Chorionic villus sampling Tube through vagina into uterus Obtain cells from placenta Greater risk of miscarriage

63 3. Embryo testing In vitro fertilization (IVF) - > Remove one cell from an early embryo > why? Implant embryo in uterus

64 Genetic profiling What type of genes would you like to know about? Predisposition genes Predict health risk for: Diabetes, cancer, Alzheimer, etc Metabolic profile How a person handles a drug Disease gene carrier status Monitor work place dangers