Biology Review.

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1 Biology Review

2 Reporting Category 1: Cell Structure and Function
B.5 The student knows how an organism grows and the importance of cell differentiation. (A) describe the stages of the cell cycle, including deoxyribonucleic acid (DNA) replication and mitosis, and the importance of the cell cycle to the growth of organisms.

3 Cell Cycle Eukaryotes’ have a cell cycle which consists of
Four Phases: G1: S: G2: M: Interphase

4 Interphase- S Phase: DNA Replication
Before a cell divides, it duplicates its DNA in a copying process called replication. This process, which occurs in the S phase of interphase of the cell cycle, ensures that each resulting cell has the same complete set of DNA molecules. DNA helicase: DNA polymerase:

5 M Phase The M phase of the cell cycle, which follows interphase, produces two daughter cells. The M phase takes its name from the processes of mitosis. During the normal cell cycle, interphase can be quite long. In contrast, the process of cell division usually takes place quickly. The M phase occurs in two main stages. The first stage of the process, division of the cell nucleus is called mitosis. The second stage, the division of the cytoplasm, is called cytokinesis.

6 4 Stages of Mitosis P M A T Source: Drawing adapted from Mitosis, Dr. Martin Huss, Arkansas State

7 Cytokinesis As a result of mitosis, two nuclei each with a duplicate set of chromosomes are formed. All that remains to complete the M phase of the cycle is cytokinesis, the division of the cytoplasm. Cytokinesis usually occurs at the same time as telophase. Once cytokinesis is complete two new daughter cells are formed. Each new daughter cell will enter into interphase.

8 One division 2n  2n (same number of chromosomes) Results in 2 genetically identical cells

9 Mitosis vs. Meiosis Meiosis Produces sex cells(Gametes for sexual reproduction) Daughter cells haploid(N) Four daughter cells produced In metaphase I chromosomes line up as homologous pairs Two nuclear divisions Daughter cells have only one member of each pair of chromosomes Daughter cells have one-half of the genes from the parent cell Generates genetic diversity through crossing over and random separation of homologous pairs of chromosomes Mitosis Produces body cells(Somatic cells for growth and repair) Daughter cells diploid(2N) Two daughter cells produced In metaphase chromosomes line up singly One nuclear division Daughter cells have two sets of chromosomes(pairs) Daughter cells are genetically identical to the parent cell Insures that all daughter cells are genetically identical

10 Reporting Category 2: Mechanisms of Genetics
The student will demonstrate an understanding of the mechanisms of genetics. (B.6) Science concepts. The student knows the mechanisms of genetics, including the role of nucleic acids and the principles of Mendelian Genetics. The student is expected to (A) identify components of DNA, and describe how information for specifying the traits of an organism is carried in the DNA;

11 DNA DNA is a polymer of nucleotides. A nucleotide is made up of three parts: a sugar, a phosphate and one of four bases In DNA, the bases are A, T, C, and G DNA’s shape is a double helix The two strands are held together by HYDROGEN bonds A binds to T C binds with G

12 DNA Replication Process of DNA copying itself Steps
DNA Unzips (Hydrogen bonds break) Each side acts as a template New DNA nucleotides are added according to base- pairing rules Two new molecules of DNA result – each with one old and one new strand. Happens in INTERPHASE (before mitosis or meiosis)

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14 Protein Synthesis Remember, genes are made of DNA and are in the nucleus Genes (DNA) contain the instruction for making  a protein In transcription, DNA is used to make mRNA in the nucleus mRNA then leaves the nucleus and goes to the ribosome In translation, tRNA then brings amino acids in the proper order to make the protein on the ribosome. Made of amino acids

15 DNA  mRNA  protein

16 Can you IDENTIFY the parts?
DNA mRNA Nucleus Cytoplasm Ribosome Codon Anticodon tRNA Amino acid Protein (polypeptide)

17 READING THE CODON CHART
Be sure to use mRNA You won’t have to memorize this! What amino acid is coded for by the DNA ATA GAG First convert DNA to mRNA ATA GAG UAU CUC UAU = tyr CUC = Leu

18 Genetics This diagram shows the cross between 2 heterozygous purple flowers Cross is: Bb x Bb Notice that 75% are purple and 25% white

19 We have two genes for each trait – this is our GENOTYPE One gene came from mom, one from dad If the genes are alike, the individual is homozygous (RR, rr) If the genes are different , they are heterozygous (Rr) Some genes are dominant and others are recessive We only show a recessive trait if we have no dominant gene RR and Rr would “look” dominant rr would look recessive

20 GENETIC TECHNOLOGY DNA FINGERPRINTING TRANSGENIC organisms Organisms that have 2 different kinds of DNA Gene cloning Uses bacteria to make human proteins like insulin Use gel electrophoresis to compare DNA fragments IF DNA matches, it’s from the same individual Evidence points to suspect 2

21 Reporting Category 1:Cell Structure and Function
B.5 The student knows how an organism grows and the importance of cell differentiation. (C) describe the roles of DNA, ribonucleic acid (RNA), and environmental factors in cell differentiation.

22 DNA What is the basic structure of DNA? What are the building blocks of DNA? What are the parts of a nucleotide? The sides of the DNA ladder are made up of what 2 alternating molecules? What does it mean to have anti-parallel strands? What makes up the steps or rungs of the ladder? What is special about the order of the nitrogen bases? What are the 4 nitrogen bases? According to the base pairing rules adenine always pairs with __________ . What type of bond hold the nitrogen bases together?

23 DNA Vocabulary Review

24 Building a DNA Model Match the nucleotides on the far right with the nucleotides in the box to complete the DNA strand. Adenine - Thymine Guanine - Cytosine

25 Protein Synthesis Genes carry the information needed by cells to produce proteins, and proteins determine traits such as coloration. So how are proteins made? Protein synthesis is the process in which cells build proteins. There are 2 main steps in protein synthesis, transcription and translation. In transcription segments of DNA serve as template to produce complementary mRNA molecules. In translation the code carried by mRNA is fed into a ribosome "machine" and causes specific amino acids to be linked together to form a protein.

26 Transcription In eukaryotic cells, mRNA is produced in the cell’s nucleus and moves to the cytoplasm to play a role in the production of proteins. Transcription requires an enzyme, known as RNA polymerase is similar to DNA polymerase. bonds A-U (Uracil not Thymine) and C-G The genetic code is read three “letters” at a time so that each “word” is three bases long and corresponds to a single amino acid. Each three letter word is called a codon.

27 Translation The sequence of nucleotide bases in an mRNA molecule is a set of instructions that gives the order in which amino acids should be joined to produce a polypeptide. Once the polypeptide is complete, it then folds into its final shape or joins with other polypeptides to become a functional protein. Translation uses another type of RNA known as tRNA. Each tRNA molecule carries just one kind of amino acid. In addition, each tRNA molecule has three unpaired bases, called the anticodon

28 Amino Acid Chart

29 Putting it All Together

30 DNA / RNA Carry genetic information Made of a chain of nucleotides
Nucleotides contain a sugar, phosphate, and a nitrogen base

31 DNA / RNA DNA Double stranded “Double Helix” Four base pairs: ATGC
Sugar is Deoxyribose Found in nucleus RNA Single stranded Four base pairs: AUCG Sugar is Ribose

32 Base Pair Rule In DNA, Adenine always pairs with Thymine, and
Guanine always pairs with Cytosine

33 Replication Making of an identical strand of DNA “semi” conservative

34 Central Dogma DNA  RNA  protein  trait

35 Transcription DNAmRNA Occurs in nucleus Complementary mRNA strand is produced from a segment of DNA

36 Translation Connects amino acids in the correct order to make a protein Occurs in the cytoplasm within the ribosomes A- amino acid B- tRNA C- anticodon D- codon E- mRNA F- Ribosome G-polypeptide

37 Codon Sequence of three mRNA nucleotides that code for an amino acid

38 Mutations Change in DNA code May cause a change in protein produced
NOT always harmful Sickle Cell Mutation

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40 When DNA is extracted from the red algae Polyides rotundus, 32% of the nitrogen bases are guanine. Based on this information, what percentage of the bases are most likely adenine? A. 9% B. 18% C. 36% D. 64% Charles A. Dana Center Science TEKS Toolkit

41 A. number of nucleic acids in the DNA molecule
The genetic instructions for an organism are contained in the DNA molecule. The instructions for a specific organism are determined by the — A. number of nucleic acids in the DNA molecule B. length of the DNA molecule C. sequence of the nitrogen bases in the DNA molecule D. type of nitrogen bases in the DNA molecule Charles A. Dana Center Science TEKS Toolkit

42 The flow of information during gene expression is —
Charles A. Dana Center Science TEKS Toolkit

43 The amino acid sequence methionine, tryptophan, and aspartic acid is coded by which set of DNA bases? A. AUGUGGGAU B. TTCTCCCTT C. UACACCGUA D. TACACCCTA Charles A. Dana Center Science TEKS Toolkit

44 A. sequence of nitrogen bases in a DNA molecule
The genes of an organism control all its biological processes by controlling the A. sequence of nitrogen bases in a DNA molecule B. synthesis of proteins in each cell C. number of chromosomes in each cell D. type of nitrogen bases in a DNA molecule Charles A. Dana Center Science TEKS Toolkit

45 For a mutation to be evolutionarily significant it—
A. changes the type of protein being produced B. has a neutral effect on an organism C. provides an advantage to the species D. causes the loss of a gene Charles A. Dana Center Science TEKS Toolkit

46 A. The first amino acid in the sequence remains isoleucine.
The DNA strand TAGTTGTTTTGC codes for the amino acid sequence isoleucine, aspartic acid, lysine, and threonine. If a point mutation takes place in the DNA, and the first triplet becomes TAT, what effect will this have on the amino acid sequence? A. The first amino acid in the sequence remains isoleucine. B. Isoleucine is replaced by methionine in the amino acid sequence. C. The amino acid sequence now includes lysine. D. The last amino acid in the sequence will become serine. Charles A. Dana Center Science TEKS Toolkit

47 A. The villagers take vitamin and mineral supplements.
Approximately 900 people live in the small isolated village of Limone in northern Italy. About 40 of the villagers have high levels of the bad blood cholesterol and low levels of the good cholesterol. However, they suffer no harmful effects. Doctors have found that these villagers produce a protein that is efficient at clearing the bad type of cholesterol from arterial plaque and moving it to the liver. Which of the following best explains this phenomenon? A. The villagers take vitamin and mineral supplements. B. There are chemicals in the water that flush out the cholesterol. C. The villagers eat a diet consisting mostly of meat and cheese. D. There is a mutation in the genes of some villagers. Approximately 900 people live in the small isolated village of Limone in northern Italy. About 40 of the villagers have high levels of the bad blood cholesterol and low levels of the good cholesterol. However, thy suffer no harmful effects. Doctors have found that these villagers produce a protein that is efficient at clearing the bad type of cholesterol from arterial plaque and moving it to the liver. Which of the following best explains this phenomenon? A. The villagers take vitamin and mineral supplements. B. There are chemicals in the water that flush out the cholesterol. C. The villagers eat a diet consisting mostly of meat and cheese. D. There is a mutation in the genes of some villagers. Charles A. Dana Center Science TEKS Toolkit

48 A The chromosomes tightly coil before the nucleus divides.
During cell division, if a chromosome breaks, a mutation occurs. Which of the following processes prevent or minimize chromosome breakage during cell division? A The chromosomes tightly coil before the nucleus divides. B. Protein synthesis takes place during the division of the cytoplasm. C. Hydrogen bonds form between nitrogen bases. D. An enzyme rearranges the nitrogen bases in a gene. Charles A. Dana Center Science TEKS Toolkit

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50 © iStockphoto.com/Alan John Lander Phillips
A photomicrograph of onion root tip cells during mitosis is shown below. © iStockphoto.com/Alan John Lander Phillips Which phase of mitosis is occurring in the cell indicated by the arrow? F Prophase G Metaphase H Anaphase J Telophase A photomicrograph of onion root tip cells during mitosis is shown below. Which phase of mitosis is occurring in the cell indicated by the arrow? F Prophase G Metaphase H Anaphase J Telophase © iStockphoto.com/Alan John Lander Phillips

51 A model of a DNA molecule is shown below.
The arrow indicates — F the bond between adjacent phosphate and deoxyribose molecules G the junction of introns and exons in the sense strand of DNA H the hydrogen bond between complementary nucleotides J the junction of a codon and a DNA triplet

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53 Characteristics such as a widow’s peak or attached earlobes are determined by the genetic code. Which components of DNA are referred to as the genetic code? F Phosphate groups G Nitrogenous bases H Deoxyribose sugars J Hydrogen bonds

54 In a DNA, the letters A, T, C, and G represent
A bases. B sugars. C proteins. D amino acids.

55 The corresponding amino acids are brought into a cell's ribosome by which type of RNA?
A messenger RNA B ribosomal RNA C transfer RNA D replication RNA

56 Which of these must occur during S phase of the cell cycle so that two daughter cells can be produced during M phase? A The DNA must be replicated. B The chromosomes must be joined. C The cytoplasm must be separated. D The cell membrane must be expanded

57 The diagram below represents the cell cycle.
When cells leave the cell cycle, they exit during G1 phase and then enter G0 phase, a resting period. Most normal cells can leave G0 phase and reenter the cell cycle at G1 phase before entering S phase. Cancer cells are different because they cannot enter G0 phase and are likely to do which of the following? A Fail to complete S phase C Repeat the cell cycle continuously B Mutate during G phase D Die after completing mitosis

58 The _____ contains spindle fibers, centrioles, and aster fibers.
A spindle apparatus B centromere C chromosome D nuclear envelope

59 What phase of cell division comes immediately after the phase shown below?
A cytokinesis C cyclin phase B prophase D anaphase

60 Which of these events does not occur during telophase?
A chromosomes arrive at cellular poles B cytoplasm splits in two C chromosomes relax D spindle apparatus disassembles

61 What structures are lined up at the center of this cell?
A cyclins C chromosomes B single chromatids D kinases