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Autosome: sex chromosome: pairs of chromosomes are called autosomes. Mar 16, Autosomes are chromosomes that don't carry any genes that determine the sex of the individual. Sex chromosomes carry sex-determining. Describe the relationship between DNA, genes, and chromosomes. Describe the difference between autosomes and sex chromosomes. autosomes are the.
There is 1 sex chromosome and 22 autosomes in a sex cell gamete also known as egg or sperm Define epigenetics and explain how epigenetic effects could cause cancer.
Cancer is caused by failure of checks and balances that control cell numbers in response to the needs of the whole organism. Define cancer as a disease, describe how it is diagnosed, and describe three ways it can be treated. Part 1 Cancer is a malignant tumor involving abnormal cell growth with the potential to invade or spread to other parts of the body.
Not all tumors are cancerous; benign tumors do not spread to other parts of the body. Part 2 Cancer is nearly always diagnosed by an expert who has looked at cell or tissue samples biopsy under a microscope, blood tests can also help in diagnosing cancer. Radiation therapy, chemotherapy, and surgery An oncogene is a gene that has the potential to cause cancer.
Describe one advantage and two disadvantages of sexual reproduction, which involves meiosis.
Part 1 Advantages of sexual reproduction: More genetic variation species Children different than parents Able to produce more offspring because of mate Part 2 Disadvantages of sexual reproduction: Slower reproduction rate Less reliable reproduction Takes time and energy to find mate Explain how a karyotype is constructed and how it can be used.
Part 1 Karyotyping is a laboratory technique used to analyze chromosomes in order to look for any major chromosomal anomaly which may cause a genetic condition. Part 2 Karyotypes are presented in a standard form. First, the total number of chromosomes is given, followed by a comma and the sex chromosome constitution.
Part 3 This shorthand description is followed by coding of any autosomal abnormalities. A few simple examples of this format are: Describe the role of sex cells in reproduction in regards to chromosome numbers. Human body cells each contain 23 pairs of chromosomes. Parents pass on their genes to their offspring in their sex cells. Describe the process of crossing over when it occurs and what happens and how it increases variation.
Part 1 crossing over is a process in genetics by which the two chromosomes of a homologous pair exchange equal segments with each other.
Crossing over occurs during prophase I of Meiosis I. Part 2 The crossing over makes more room for variability. When the chromosomes swap traits, they create different combinations of traits.
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The different combinations causes more variations in the products Describe how crossing over percentages can be used to create a gene map for a chromosome.
However, a small percentage of humans have a divergent sexual development, known as intersex. This can result from allosomes that are neither XX nor XY.
It can also occur when two fertilized embryo fuse, producing a chimera that might contain two different sets of DNA one XX and the other XY. It could also result from exposure, often in utero, to chemicals that disrupt the normal conversion of the allosomes into sex hormones and further into the development of either ambiguous outer genetilia or internal organs.
Genes that are carried by either sex chromosome are said to be sex linked. Sex linked diseases are passed down through families through one of the X or Y chromosomes. Since only men inherit Y chromosomes, they are the only ones to inherit Y-linked traits.
Men and women can get the X-linked ones since both inherit X chromosomes. Dominant inheritance occurs when an abnormal gene from one parent causes disease even though the matching gene from the other parent is normal.
The abnormal allele dominates.
Recessive inheritance is when both matching genes must be abnormal to cause disease. If only one gene in the pair is abnormal, the disease does not occur, or is mild. Someone who has one abnormal gene but no symptoms is called a carrier. A carrier can pass this abnormal gene to his or her children. Most of them code for something other than female anatomical traits. Many of the non-sex determining X-linked genes are responsible for abnormal conditions. The Y chromosome carries about 78 genes.
Most of the Y chromosome genes are involved with essential cell house-keeping activities and sperm production. Only one of the Y chromosome genes, the SRY gene, is responsible for male anatomical traits. When any of the 9 genes involved in sperm production are missing or defective the result is usually very low sperm counts and infertility. Color blindness or color vision deficiency is the inability or decreased ability to see color, or perceive color differences, under normal lighting conditions.
Color blindness affects many individuals in the population. There is no actual blindness, but there is a deficiency of color vision. The most usual cause is a fault in the development of one or more sets of retinal cones that perceive color in light and transmit that information to the optic nerve. This type of color blindness is usually a sex-linked condition.