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Examination 3
Examination 3

... - During S phase, DNA is replicated giving rise to chromosomes consisting of two sister chromatids o Prophase 1 - Spindle formation - Breakdown of nuclear envelope - Nucleoli disappear - Chromosomes condense - Each chromosome consists of two chromatid from S phase of interphase - Homologous chromoso ...
Student Exploration Sheet: Growing Plants - aiss-science-9
Student Exploration Sheet: Growing Plants - aiss-science-9

... E. What is the role of the centrioles? Centrioles produce spindle fibres and help to Organize the movement of chromosomes. F. In which phase does a new nuclear membrane develop? Telophase G. A cell has a single line of chromosomes. What is the phase? Metaphase H. During which three phases are indivi ...
Integrated Teaching Area (ITA) Scenarios for Semester One
Integrated Teaching Area (ITA) Scenarios for Semester One

... What is the normal human chromosome complement, how do these divide at (a) meiosis and (b) mitosis? 46 XX (female) or 46 XY (male) i.e. 22 pairs or autosomes and the sex chromosomes. Chromosomes are recognised by their size and banding pattern. Mitosis is the production of two diploid daughter cells ...
Guided Reading Chapter 1: The Science of Heredity Section 1-1
Guided Reading Chapter 1: The Science of Heredity Section 1-1

... a. Grasshopper sex cells have half the number of chromosomes as body cells. b. Grasshopper body cells have half the number of chromosomes as sex cells. c. Grasshopper body cells and sex cells have the same number of chromosomes. d. When grasshopper sex cells join, the fertilized egg has the same num ...
Unit 3 - kehsscience.org
Unit 3 - kehsscience.org

... Every organism that reproduces sexually has an even number of chromosomes in the nucleus of each of their body cells…..this is because ½ of them came from the mother’s ______ and ½ came from the father’s ___________. For example, humans have a total of ______ chromosomes in every body cell -- ____ c ...
Mendelian Genetics, cont. Thursday, October 30, 2008 SI Leader
Mendelian Genetics, cont. Thursday, October 30, 2008 SI Leader

... 8. What possible GENOTYPES for A, B, AB, and O blood exist? (hint: you can draw out the Punnet square if needed -> O A B along the top and O A B along the side). What PHENOTYPES do each genotype display? ...
Mendelian Genetics
Mendelian Genetics

... Dominant-recessive inheritance—interaction of dominant and recessive alleles where dominant trait masks recessive trait a. Dominant traits are always expressed i. Any single dominant allele results in the expression of that trait ...
Heredity Basics
Heredity Basics

... control the traits that show up in an organism. The different forms a gene may have for a trait is an allele. (During MEIOSIS, a pair of chromosomes separate and the alleles move into separate gametes. Each gamete now contains 1 allele for each trait.) ...
Section 8.2 Summary – pages 201
Section 8.2 Summary – pages 201

... • During Interphase, under a microscope, there doesn’t appear to be much going on. • BUT, Interphase is the busiest phase of the cell cycle • During this time the cell is growing, making more organelles, and chromatin (DNA) is replicating. ...
1. Overview of Cell Division Roles of Cell Division 10/11/2015 1
1. Overview of Cell Division Roles of Cell Division 10/11/2015 1

... • results in the division of the cell nucleus • the cell may or may not undergo cytokinesis ...
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... the centromeres of chromosomes. Chromosomes are attached to polar fibres at their kinetochores via kinetochore fibres. Lamins: The fibrous proteins providing structural function and transcriptional regulation in the cell nucleus. Nuclear lamins interact with membraneassociated proteins to form the n ...
Chapter 8
Chapter 8

... only once, during the preceding interphase. – The number of cell divisions varies: • Mitosis uses one division and produces two diploid cells • Meiosis uses two divisions and produces four haploid cells – All the events unique to meiosis occur during meiosis I, while meiosis II is the same as mitosi ...
Answers to pgs. 73 - 75 wks.
Answers to pgs. 73 - 75 wks.

... 32. After which stage in the cell cycle is each new cell an exact copy of the parent cell? a. interphase b. mitosis c. cytokinesis d. prophase ...
Pre-lab Homework Lab 2: Mitosis and the Cell Cycle
Pre-lab Homework Lab 2: Mitosis and the Cell Cycle

... The cell cycle is the process in which one parent cell becomes two new daughter cells. The resulting two cells are genetically identical to each other and genetically identical to the parent cell. Most of your contain 46 chromosomes, 23 inherited from your mom, 23 inherited from your dad. The goal o ...
GENETICS
GENETICS

... called a point mutation ACGUCAGUA  Threonine—Serine—Valine ACGUUAGUA  Threonine—Leucine—Valine Depending on where the mutation occurs, it may have no affect on the protein ACGUCAGUA  Threonine—Serine—Valine ACGUCGGUA  Threonine—Serine—Valine Wobble: Base pairing between codon and anticodon in wh ...
Mastering Biology Genetics Retake
Mastering Biology Genetics Retake

... spindle fibers move the homologous chromosomes to ______ 2) prophase II opposite poles of the cell. ______ 3) telophase I c. Chromosomes line up at the equator. d. Pairs of homologous chromosomes line up at the equator. ______ 4) metaphase II ...
2nd 9 Weeks Study Guide! Aren`t you excited?? Chapter 10
2nd 9 Weeks Study Guide! Aren`t you excited?? Chapter 10

... Learning Target 2: I can indentify and explain Mendal’s law of segregation and law of independent assortment Mendal’s law of segregation states that during meiosis, the factos that control each trait separate, and only ______________________________ from each pair is/are passed to the offspring. The ...
Bloom level questions
Bloom level questions

... Answer: mitosis occurs everyday and probably my lifetime in my body because many cells are needed to grow, many cells such as blood and skin cells need to be replaced, and in the case of injury cells are damaged and also need to be replaced. Meiosis only occurs to produce sex cells and in human fema ...
Human Genetics
Human Genetics

... assumed that each different trait we discussed were on a different pair of chromosomes what if we’re considering two different unrelated traits on the same chromosome genes on the same chromosome cannot separate  they move as a unit during meiosis such genes are said to be linked but linked genes ...
The Human Genome Chapter 14
The Human Genome Chapter 14

... Blood Group Genes- knowing a person’s blood group is crucial for procedures like blood transfusion because, putting the wrong type of blood into a patient during a transfusion could be fatal. The best known groups are the ABO and the Rh blood groups. Rh- stands for “rhesus monkey.” It is determined ...
Document
Document

... The sporophyte is dependent on the gametophyte. The sporophyte is large, and the gametophyte is small and independent. The gametophyte is reduced and dependent on the sporophyte. The spore is the main means of dispersing the offspring. A film of water is necessary for sperm to come in contact with e ...
02 Mitosis and Cytokinesis
02 Mitosis and Cytokinesis

... Cytokinesis is the final stage of cell division in eukaryotes as well as prokaryotes. During cytokinesis, the cytoplasm splits in two and the cell divides. Cytokinesis occurs somewhat differently in plant and animal cells, as shown in Figure 1.5. In animal cells, the plasma membrane of the parent ce ...
Markscheme
Markscheme

... A. Allele pairs separate during gamete formation and recombine during fertilization. B. Allele pairs for different genes separate independently during gamete formation. C. Unlinked alleles are assorted with a 9 : 3 : 3 : 1 ratio in a dihybrid cross. D. Allele pairs for the same gene are assorted ind ...
Practice Test for Biology Lab Material II
Practice Test for Biology Lab Material II

... states that when meiosis occurs and gametes form, the members of pairs of alleles become separated and are not matched up again until the zygote is formed as egg and sperm unite in fertilization. ...
Chapter 12
Chapter 12

... Distribution of Chromosomes During Eukaryotic Cell Division • In preparation for cell division, DNA is replicated and the chromosomes condense • Each duplicated chromosome has two sister chromatids (joined copies of the original chromosome), which separate during cell division • The centromere is t ...
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Meiosis



Meiosis /maɪˈoʊsɨs/ is a specialized type of cell division which reduces the chromosome number by half. This process occurs in all sexually reproducing single-celled and multi-celled eukaryotes, including animals, plants, and fungi. Errors in meiosis resulting in aneuploidy are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities. In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells each with half the number of chromosomes as the original parent cell. The two meiotic divisions are known as meiosis I and meiosis II. Before meiosis begins, during S phase of the cell cycle, the DNA of each chromosome is replicated so that it consists of two identical sister chromatids. In meiosis I, homologous chromosomes pair with each other and can exchange genetic material in a process called chromosomal crossover. The homologous chromosomes are then segregated into two new daughter cells, each containing half the number of chromosomes as the parent cell. At the end of meiosis I, sister chromatids remain attached and may differ from one another if crossing-over occurred. In meiosis II, the two cells produced during meiosis I divide again. Sister chromatids segregate from one another to produce four total daughter cells. These cells can mature into various types of gametes such as ova, sperm, spores, or pollen.Because the number of chromosomes is halved during meiosis, gametes can fuse (i.e. fertilization) to form a zygote with a complete chromosome count containing a combination of paternal and maternal chromosomes. Thus, meiosis and fertilization facilitate sexual reproduction with successive generations maintaining the same number of chromosomes. For example, a typical diploid human cell contains 23 pairs of chromosomes (46 total, half of maternal origin and half of paternal origin). Meiosis produces haploid gametes with one set of 23 chromosomes. When two gametes (an egg and a sperm) fuse, the resulting zygote is once again diploid, with the mother and father each contributing 23 chromosomes. This same pattern, but not the same number of chromosomes, occurs in all organisms that utilize meiosis. Thus, if a species has 30 chromosomes in its somatic cells, it will produce gametes with 15 chromosomes.
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