Chromosomes, Karyotypes, Mitosis & Meiosis Study Guide PDF

Chromosomes, Karyotypes, Mitosis and Meiosis STUDY GUIDE EXAM DAY: Friday, 1/14/25 G DAY How many cells do you think there are in your body? __________ Why are there so many cells as opposed to one large cell?...

Chromosomes, Karyotypes, Mitosis and Meiosis STUDY GUIDE EXAM DAY: Friday, 1/14/25 G DAY How many cells do you think there are in your body? __________ Why are there so many cells as opposed to one large cell? Give specific reasons. Be sure to discuss surface area and volume as well as specialization. trillions of cells Having small cells allows for efficiency and cell specialization. Small cells are more efficient than large cells because they have more surface area to volume ratio as compared to larger cells. Smaller cells can carry out specialized functions whereas one large cell can not specialize. How do you think a single cell developed into all the cells in your body? One single cell called a ZYGOTE must have undergone several rounds of MITOSIS to create trillions of cells. ALL CELLS then MUST carry the same chromosomes (genes). However, some cells express certain genes while others do not, making them SPECIALIZED. What is a term for cells that divide uncontrollably? Cancer When cancer spreads, what is the term for this? Metastasis What are checkpoints in the cell cycle? Can you name all 3 of them? G1, G2 and M checkpoints monitor cells as they move through the phases of the cell cycle. The purpose of checkpoints is to ensure that cells are ready to move to the next phase and also to prevent defective cells from completing the cell cycle. Chromosome Basics: Word Bank: n​ ​ 2n​ ​ diploid​​ chromosome​ ​ gametes​ ​ centromere​ ​ homologous​ haploid telomeres​ somatic cell A strand of coiled up DNA containing genetic information ____________________ Chromosome What is the name for the pair shown in the picture to the right? _______________ homologous pair What is the structure labeled A? _______________________ centromere What is the structure labeled B? _______________________ telomeres The pair shown can only be found in what type of cells? _____________________ somatic Another name for having two sets of chromosomes is called what? ____________ diploid An abbreviation for diploid is _______________ Another name for having only one set of chromosomes is called what? ___________________ haploid An abbreviation for haploid is __________________ n An example of haploid cells is a __________________, which is another name for the sex cells (egg and sperm) gamete Word Bank: 23 2 DNA Chromosome genome gene Each _______________________contains a long molecule of DNA chromosome We have ______ versions of every chromosome since we get one from each parent. 2 Each ________ molecule contains many genes. DNA A _________ is a segment of a DNA molecule that gives the instructions for making a protein. Many of these proteins are needed for normal cell structure and function. gene The entire amount of DNA in every cell is called the _______________ and is organized into _______ pairs of chromosomes. genome, 23 Haploid or Diploid: Which one? Humans have a 46 total chromosomes __________________ diploid Human gametes have 23 chromosomes _________________ haploid Humans have 23 pairs of homologous chromosomes ____________________ diploid What is the Haploid or Diploid Number? A somatic cell with 12 chromosomes has ____________ chromosomes in the gametes. 6 A chicken has 20 chromosomes so how many pairs is that? _______________ 10 pairs What is the haploid number if the diploid number is 10? _______________ 5 The haploid number is 30 so the diploid number must be? _____________ 60 What is the diploid number if the haploid number is 4? _______________ 8 What is the haploid number if the diploid number is 40? ______________ 20 Haploid cells have ___________ as many sets of chromosomes as diploid cells. half MITOSIS KEY POINTS: Give 3 specific reasons why cells divide: 1.​ growth 2.​ repair 3.​ to stay small (efficiency and specialization) Cells divide by mitosis as part of the M phase of the cell cycle. At the end of mitosis, how many cells are there? ________ Are these cells haploid or diploid? _________ Are they identical? ________. Mitosis is defined as ________________ division while cytokinesis is ___________ division. 2, diploid, yes, nuclear, cellular 2 Karyotypes: How many total chromosomes? 46 The pairs are called _________________. homologous The dark bands on the chromosomes represent ____________. genes What are genes? piece of DNA that codes for protein What do genes code for? protein Are these chromosomes from a haploid or diploid cell and how do you know? diploid as there are 2 sets (one pink set that came from the ovum and one blue set that came from the sperm) Is the karyotype from a male or female? male What is the male sex chromosomes? Y What is the female sex chromosomes? X Is this a normal karyotype? yes How do you know? there are 2 chromosomes at each number including 2 sex chromosomes Edwards Syndrome is an example where nondisjunction occurs. Define nondisjunction. when chromosomes (either homologous pairs or sister chromatids) do not separate (disjoin) in meiosis 1 (homologous pairs) or meiosis 2 (sister chromatids)- during Anaphase 1 or Anaphase 2 What occurs to the chromosomes in Edward’s Syndrome? there is an extra chromosome at #18 due to nondisjunction of the 18th pair either during Meiosis 1 or 2 (specifically Anaphase 1 or 2) Another name for Edward’s Syndrome is Trisomy ___________. What do you know about chromosomal mutations vs gene mutations in terms of how bad they are? Think about it. Chromosomes are made of genes. If an entire chromosome (which is bigger than a gene) is mutated, which is likely to be worse? ____________________ mutations. chromosomal mutations are worse because many genes are impacted by the mutation. BONUS: How would a genetic counselor know that the other somatic cells in a patient will have the same condition as the one seen? Hint- think about how somatic cells reproduce! ALL somatic cells contain the SAME CHROMOSOMES because they were made from MITOSIS. Chromosomal mutations: 3 List the names of the chromosomal mutations: 1.​ inversion 2.​ duplication 3.​ translocation 4.​ deletion Genes code for Proteins: The sequence of the genes on the chromosome code for a specific ________________. protein Suppose there is a chromosome with parts A, B, C , D (in this order). IF Gene C relocates to another part of the chromosome, what is the consequence? the protein that was originally intended to be made will change also as genes code for proteins. IF gene A were to be deleted, what would be the consequence? Again, the proteins that are encoded by the DNA in this part of the chromosome called A would not be made as the code was deleted The altered gene sequence may produce a __________________protein due to this mutation. mutated Mitosis: Each cell in your body was produced by one cell dividing into ______ two daughter cells. This figure summarizes how a cell divides into two _______________ genetically identical daughter cells. The Cell Cycle – How One Cell Becomes Two identical Cells 4 Circle the cell in the figure that represents both a daughter cell that has been produced by the cell cycle and a cell that is beginning the cell cycle. This figure shows how one cell becomes two daughter cells. This cell cycle includes: ​ the ________ phases when the cell makes more cytoplasm and grows G1 ​ the_____phase when the DNA in each chromosome is replicated to produce two identical copies of each chromosome S ​ _________, when the two copies of each chromosome are separated to opposite ends of the cell Anaphase ​ ___________ when the cell divides into two daughter cells, each with a complete set of chromosomes. cytokinesis In the figure, the cells at each phase of the cell cycle are shown as being the same size. In reality, the daughter cells are ____________the cells at the end of the G1, S and G2 phases. a. bigger than b. smaller than c. the same size as smaller than Bonus: The cell below is about to undergo mitosis. What will the chromosomes in the 2 daughter cells look like? Think-will the chromosomes in the daughter cells be duplicated? Each new cell should have 4 chromatids each. Note, chromatids, not duplicated chromosomes. Interphase includes all of the cell cycle except mitosis and cytokinesis, so interphase includes the ______, ______ and ______ phases. G1 S, G2 5 This figure shows six stages of cell division for a cell that has two pairs of chromosomes, but these stages are not shown in the correct sequence. ​ Put a star next to the cell in Metaphase. ​ Use a square to show when sister chromatids separate to form individual chromosomes. ​ Put a circle near the cell in telophase ​ Put an arrow to the cell in cytokinesis ​ Are the chromosomes in the TELOPHASE cell duplicated? No! In telophase, the chromosomes appear as chromatids as they are the result of Anaphase, which separates the duplicated chromosomes Word Bank: genes, zygote, homologous, gametes, oogenesis, spermatogenesis, reproductive, unique Meiosis is a special type of cell division in multicellular organisms. It occurs in the _____________________organs. What is meiosis in males called? ___________________________________ How about females? ____________________________. What is the name of the cell that undergoes meiosis? ___________ cell. This cell is diploid meaning it has ______ copies of every chromosome. These chromosomes are _________________________, meaning they are the same size and carry the same ___________. Unlike mitosis, meiosis produces ____________ genetically _______________ daughter cells called ________________________. These gametes participate in fertilization to form a ________________, a fertilized egg. reproductive spermatogenesis oogenesis germ cell (it is somatic/2n) 2 diploid 2 homologous genes 4 UNIQUE sex cells/gametes zygote 6 Meiosis is very different from mitosis in that the four daughter cells produced are genetically unique. Name three specific ways genetic diversity is achieved during the following phases of meiosis. 1.​ Prophase 1: __________________________ 2.​ Meiosis 1: ___________________________ 3.​ How can genetic diversity be achieved after meiosis? ___________________ mating and _______________ fertilization. Prophase 1: Crossing over/recombination Meiosis 1: (mistake! should say METAPHASE 1)- Independent assortment random random Compare and contrast: 18. Indicate whether the characteristic applies to mitosis, meiosis, or both, by checking the box. Mitosis Meiosis Pairing of homologous chromosomes occur x Two divisions x Two daughter cells produced x Chromosome number is halved x Involves duplication of chromosomes x x Crossing over occurs x Associated with growth and asexual reproduction x Associated with sexual reproduction x Produces gametes x Associated with cancer x Produces identical daughter cells x Recombination occurs x Occurs in plants and animals x x Four daughter cells are produced x 7