Molecules of Life notes on Chapter 2
Molecules of Life notes on Chapter 2 HNR 247
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This 5 page Class Notes was uploaded by Julia Dang on Sunday February 7, 2016. The Class Notes belongs to HNR 247 at Grand Valley State University taught by Dr Debra Burg in Winter 2016. Since its upload, it has received 14 views. For similar materials see Molecules of Life in Perspective in OTHER at Grand Valley State University.
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Date Created: 02/07/16
Lecture 8 2-4-16 HNR 247 A. Mitosis (binary fission)- 1 cell 2 cells. Goal is to make more cells B. Meiosis- 1 cell 4 cells with half the chromosomes. (sperm and eggs) Gametes Sexual reproduction Pass on info to the next generation C. Haploid: 1 copy of each chromosome. Can’t do sexual reproduction with these. You can’t each give one chromosome and can’t each give half a chromosome. D. Diploid: 2 chromosomes (pairs) 1 egg + 1 sperm 2 chromosomes o Each parent provides one. E. Genome: Total genetic material for an organism F. Genetics: More to do with study of the specific genes and the functions, the inheritance of genes. G. DNA is coiled and compact enough to move and be malleable H. The cell cycle: the process from finishing cell division and the length of time it takes to make two cells. The cell only spends 10% of the time dividing G= gap; s= synthesis; M= mitosis G1: protein synthesis- making a lot of enzymes and regulatory proteins (controlling the process) And checking the DNA (making sure there’s no mutations or anything that needs to be fixed) o A cell might hangout in G1 for a while if it’s not ready o It might even trigger it’s own death so it won’t go about reproducing cells that aren’t right. Checkpoint! Make sure there’s everything that’s ready to go. If it’s not okay, then they wouldn’t move on to S. S replicates the DNA G2: proof reads and fixes if needed. M: Mitosis- one cell dividing into two. I. Two ways a cell can die: Necrosis: it basically falls apart. It’s damaged. Everything disintegrates. Spews out contents- they’re released into whatever environment. Apoptosis: triggered to commit suicide- DNA is cut up into small fragments. Cell starts to shrink. Blebbing happens. Then phagocytes come and clean up the cells and eat them. o Series of protease that trigger this o DNAase J. Humans have 23 pairs of chromosomes. Karyotype: chromosomes in the condensed form. Steps of mitosis! 1. Replicate chromosomes- S phase. 2. Mitosis a. Line up the chromosomes and the splitting of the cell b. Spindle fibers pull them apart—Split Meiosis One cell: 46 4 cells: 23 1. Replicate once a. Make sister chromatids- they’re connected. b. They’re side by side, rather than single file like the mitosis. c. Sister chromatid exchange/recombination/crossing over: The arms that are by each other can cross over and there’s an enzyme that cuts the back bone and what was once on one is now a part of the other. i. The purpose: variation- the more variety there is the more likely they’ll survive. 2. Divide twice a. Spindle fibers pull the chromosomes apart b. Then the spindle fibers pull again and the chromosomes are separated- they’re haploids- they’re gametes. Translocation: swapping parts with a different chromosomes- it’s not good- causes cancers. HNR 247 2-2-16 Lecture 6 Chapter 2 A. Transcription: B. Translation: translating mRNA into amino acids. C. a. There’s a stop codon and the whole thing kind of disassembles. b. A ribosome can attach and start the process again… c. There’s the protein! i. Sometimes it needs additional things like sugars and what not. D. DNA replication: a. One is the original and the other one replicates to form with what is already there. b. When you put the wrong base in, it’s a mutation. i. There’s two ways it can be fixed: it has proof reading ability with enzymes (it can back up, remove the wrong base and put in the right one.) ii. How does it know it’s not right? 1. It wouldn’t form really good bonding- the enzyme sees the original one and sees that there’s the wrong match- wrong shape. c. Sometimes when it’s replicated, it becomes abnormal, but it isn’t changed because the matches are still alright. i. Sometimes this causes diseases though 1. Specifically, cancers take several abnormalities, though. E. mRNA processing: by eukaryotes. Prom Gene Prom Exon Intron Ex 2 INT Ex 3 o Intron = intervening sequence o “junk DNA” –it’s not necessary or useful for the specific one. o Exons code for gene 1. Transcription of all 2. Enzyme to cut out introns 3. Piece together exons 4. Translation o Substitutions- one base for another- reading frame is still the same. o May or may not change the amino acid o May or may not change the function of the protein o Additions and deletions- Always shift the reading frame. Might generate a stop codon. Likely change amino acid after addition or deletion.