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... 55. What is a chromosome? 56. What is a histone? 57. Why do your cells make chromosomes from chromatin? 58. What is a chromatid? 59. What is a centromere? 60. What is a kinetochore? 61. What is the difference between a haploid and diploid cell – how many chromosomes are found in each type of cell fo ...
Slides on chromosomal changes
Slides on chromosomal changes

... 2) A number of crop plants have undergone such changes and chromosome manipulation may be important in agriculture (breeding). 3) A number of such changes are responsible for human genetic diseases. 4) They may disrupt gene function directly if a break occurs in a gene. 5) Can lead to genetic redund ...
BARBARA McCLINTOCK-Biography
BARBARA McCLINTOCK-Biography

... gametic cells. Consequently, a few gametes ma)- be formed with Ds or Ac or both, located at new positions. Following such transposition, each remains at the new location until, in a subsequent cell or plant generation, transposition to another location again occurs ...
Lecture 3: Chromosomes and sex determination
Lecture 3: Chromosomes and sex determination

... Inheritance of X-linked recessive traits in humans Examples: ¾ hemophilia - inability of blood to clot, caused by defective Factor VIII, there are also other types; ¾ Duchenne’s muscular dystrophy - fatal, death by early adulthood; ¾ red-green color blindness; ¾ testicular feminization syndrome (an ...
Cell wk 8
Cell wk 8

Chapter 10: Meiosis
Chapter 10: Meiosis

... Prophase I: Homologous chromosomes pair up (form tetrad); Cross over may occur; other aspects as observed in mitosis. Metaphase I: Homologous pairs align at equator (not sister chromatids). ...
Meiosis and Mendel`s Law of Segregation
Meiosis and Mendel`s Law of Segregation

... the process of meiosis. Meiosis is the process in which a diploid germ cell, diploid meaning that the cell has two sets of chromosomes – one from each parent, first replicates its DNA and then undergoes two rounds of division to produce four haploid gametes. The resulting products of meiosis, or gam ...
INHERITANCE
INHERITANCE

... Inheritance is the passage of hereditary traits from one generation to the next. It is the process by which you acquired your characteristics from your parents and transmit some of your traits to your children. The branch of biology that deals with inheritance is called genetics. Genotype and Phenot ...
The Chromosomes of a Frimpanzee
The Chromosomes of a Frimpanzee

... UCLA, GK-12 Science & Mathematics in Los Angeles Urban Schools http://www.nslc.ucla.edu/STEP/GK12/ ...
Section 6.3- Mendelian Genetics
Section 6.3- Mendelian Genetics

What Does an Owl Eat
What Does an Owl Eat

... UCLA, GK-12 Science & Mathematics in Los Angeles Urban Schools http://www.nslc.ucla.edu/STEP/GK12/ ...
Genetics Quiz – 18 October 2005
Genetics Quiz – 18 October 2005

... 1. Somatic cells include all body cells with the exception of gamete producing cells True 2. Gametes (sperm or egg) are diploid, that is they have half the number of chromosomes of either parent False 3. mitosis occurs in gametes producing four identical diploid cells False 4. the diversity of human ...
Exam II Study Guide  Chapter 8:  Cellular Reproduction cell cycle
Exam II Study Guide Chapter 8: Cellular Reproduction cell cycle

... Know the difference between chromatin, chromosome, and sister chromatid. Understand the different levels of DNA structure and packing—from the double helix up to the condensed chromosomes of mitotic cells. Understand the difference between mitotic and meiotic divisions. Know the terms ploidy, haploi ...
Chapter 12 Summary
Chapter 12 Summary

... to be diploid. Diploid means “two sets.” • Gametes have half the number of chromosomes as their parent cells. Cells that have only one set of chromosomes are said to be haploid. Gametes are genetically different from the parent cell and from one another. Before meiosis begins, cells undergo DNA repl ...
Variation and the Monohybrid Cross
Variation and the Monohybrid Cross

... Significance of meiosis Allele: gene ...
080701Genes and chromosomes
080701Genes and chromosomes

... It is estimated that one in 25 people carry the recessive defective gene (on autosomal chromosome 7) for cystic fibrosis (CF). If two carriers have a baby, there is a 25% risk of it having CF. Incidence of CF in Western Europe is approximately one in 2,000 (Turnpenny and Ellard, 2007). The faulty ge ...
DNA Replication
DNA Replication

... genotypes are transmitted during cell division. ...
What are genomes and how are they studied
What are genomes and how are they studied

...  Transfer of 1-200kb blocks of genomic sequence  Segmental duplications can occur on homologous chromosomes (intrachromosomal) or non homologous chromosomes (interchromosomal)  Not always tandemly arranged  Relatively recent Interchromosomal segments Intrachromosomal  duplicated among non homol ...
document
document

... an organism. If both alleles are the same, the organism is homozygous for the trait. If both alleles are different, the organism is heterozygous for that trait. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygos. Most eukaryotes have two matching sets of c ...
Comparative Genomics II.
Comparative Genomics II.

... Each chromosome looks more like the letter X, with each arm in two replicates (sister chromatids) emanating from the centromere. The shorter arm is designated as the “p” arm (petit- little); the longer arm is labeled the “q” arm (queue-tail). ...
COMPLEX PATTERNS OF INHERITANCE
COMPLEX PATTERNS OF INHERITANCE

... including those that will give rise to the hairproducing skin cells A female that is heterozygous will have one or the other X inactivated in different groups of cells resulting in patches of black and orange fur ...
DNA
DNA

... Black Brown Red ...
First Semester Final
First Semester Final

... • Anything that has mass and takes up space and is made up of different kinds of atoms; includes all things that can be seen, tasted, smelled or touched but DOES NOT include heat, sound or light. ...
Adenine - /ad·e·nine/ - One of four bases found in the nucleotides of
Adenine - /ad·e·nine/ - One of four bases found in the nucleotides of

... such as hair color or blood type or even diseases. In an individual, one allele (the dominant form) may be expressed more than another form (the recessive one). Different alleles of DNA sequences when not located in genes do not produce variations in inherited characteristics or diseases. Mutations ...
Mitosis and Cell Division
Mitosis and Cell Division

... • End up with: ‘A’ and ‘B’ on Chrm II, with A farther right than B • Ab and AB ...
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Chromosome



A chromosome (chromo- + -some) is a packaged and organized structure containing most of the DNA of a living organism. It is not usually found on its own, but rather is complexed with many structural proteins called histones as well as associated transcription (copying of genetic sequences) factors and several other macromolecules. Two ""sister"" chromatids (half a chromosome) join together at a protein junction called a centromere. Chromosomes are normally visible under a light microscope only when the cell is undergoing mitosis. Even then, the full chromosome containing both joined sister chromatids becomes visible only during a sequence of mitosis known as metaphase (when chromosomes align together, attached to the mitotic spindle and prepare to divide). This DNA and its associated proteins and macromolecules is collectively known as chromatin, which is further packaged along with its associated molecules into a discrete structure called a nucleosome. Chromatin is present in most cells, with a few exceptions - erythrocytes for example. Occurring only in the nucleus of eukaryotic cells, chromatin composes the vast majority of all DNA, except for a small amount inherited maternally which is found in mitochondria. In prokaryotic cells, chromatin occurs free-floating in cytoplasm, as these cells lack organelles and a defined nucleus. The main information-carrying macromolecule is a single piece of coiled double-stranded DNA, containing many genes, regulatory elements and other noncoding DNA. The DNA-bound macromolecules are proteins, which serve to package the DNA and control its functions. Chromosomes vary widely between different organisms. Some species such as certain bacteria also contain plasmids or other extrachromosomal DNA. These are circular structures in the cytoplasm which contain cellular DNA and play a role in horizontal gene transfer.Compaction of the duplicated chromosomes during cell division (mitosis or meiosis) results either in a four-arm structure (pictured to the right) if the centromere is located in the middle of the chromosome or a two-arm structure if the centromere is located near one of the ends. Chromosomal recombination during meiosis and subsequent sexual reproduction plays a vital role in genetic diversity. If these structures are manipulated incorrectly, through processes known as chromosomal instability and translocation, the cell may undergo mitotic catastrophe and die, or it may unexpectedly evade apoptosis leading to the progression of cancer.In prokaryotes (see nucleoids) and viruses, the DNA is often densely packed and organized. In the case of archaea by homologs to eukaryotic histones, in the case of bacteria by histone-like proteins. Small circular genomes called plasmids are often found in bacteria and also in mitochondria and chloroplasts, reflecting their bacterial origins.
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