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45 Cards in this Set
- Front
- Back
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heredity |
the passing of traits from parents to offspring |
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Gregor Mendel |
a scientist (who was a monk/priest) whose discoveries form the foundation of genetics
(pea plant experiments; heredity) |
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alleles |
the different forms of a gene |
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gene |
-the set of info. that controls a trait
-a segment of DNA on a chromosome that codes for a specific trait |
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dominant allele |
an allele whose trait always shows up in the organism when the allele is present |
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recessive allele |
an allele that is masked when a dominant allele is present |
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probability |
a number that describes how likely it is that an event will occur |
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punnett square |
a chart that shows all the possible combinations of alleles that can result from a genetic cross |
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genotype |
an organism's genetic makeup or allele combinations |
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phenotype |
an organism's physical appearance or visible trait |
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homozygous |
having 2 identical alleles for a trait (a purebred) |
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heterozygous |
having 2 different alleles for a trait (a hybrid) |
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chromosome |
a doubled rod of condensed chromatin |
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sex chromosomes |
a pair of chromosomes carrying genes that determine whether a person is female or male |
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carrier |
a person who has 1 recessive allele for a trait, but does not have the trait
(making them still able to pass down the trait to their offspring) |
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pedigree |
a chart or "family tree" that tracks which members of a family have a particular trait |
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karyotype |
a picture of all the chromosomes in a cell arranged in pairs |
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genome |
all of the DNA in one cell of an organism |
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The Human Genome Project |
a project w/ the main goal to identify the DNA sequence of every gene in the human genome |
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codominance |
when the alleles are neither dominant nor recessive, resulting in both alleles expressed in the offspring |
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Walter Sutton |
-an American geneticist who had the idea known as the chromosome theory of inheritance, stating that genes are carried from parents to their offspring on chromosomes
-examined grasshopper body cells & sex cells, and how sex cells have half the original chromosomes as body cells, but when the sperm & egg join during fertilization, the offspring gets the exact same # of chromosomes in its body cells as its parents and a set of alleles from each parent |
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meiosis |
-the process by which the # of chromosomes is reduced by half to form sex cells (eggs & sperm)
-when the chromosome pairs in a body cell separate and are distributed to 2 different cells, resulting in sex cells that have only half as many chromosomes as the other cells in the organism |
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What are chromosomes and how many pairs do humans have in their body cells? |
-Chromosomes are made up of many genes joined together like beads on a string.
-Humans have only 23 pairs of chromosomes, but each body cell contains about 35,000 genes that each control a trait
-In a chromosome pair, one chromosome is from your mom and one is from your dad, and they each have the same lineup of genes. |
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genetic code |
the order of the nitrogen bases along a gene forms a genetic code that specifies what type of protein will be produced |
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What are the 4 nitrogen bases in DNA? |
adenine (A), thymine (T), guanine (G), & cytosine (C) |
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protein synthesis |
when the cell uses info. from a gene on a chromosome to produce a specific protein |
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messenger RNA |
copies the coded message from the DNA in the nucleus and carries the message to the ribosome in the cytoplasm |
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transfer RNA |
carries amino acids to the ribosome and adds them to the growing protein |
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mutation |
-any change in a gene or chromosome
-can cause a cell to produce an incorrect protein during protein synthesis, and the organism's trait/phenotype may bb different from what it normally would have been
-can be either harmful, helpful, or neither |
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multiple alleles |
three or more forms of a gene that code for a single trait |
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What are the 4 different blood types? |
A (AA or Ai), B (BB or Bi), AB (AB), or O (ii) |
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sex-linked genes |
genes on the X and Y chromosomes; are passed from parent to child on a sex chromosome
(control sex linked traits such as colorblindness) |
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Many of a person's characteristics are determined by an interaction between _______ and _______. |
genes, the environment |
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genetic disorder |
-an abnormal condition that a person inherits through genes or chromosomes
-some are caused by mutations in the DNA of genes, while others are caused by the overall structure or # of chromosomes |
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cystic fibrosis |
-a genetic disorder in which the body produces abnormally thick mucus in the lungs and intestines, making it hard for the affected person to breathe
-caused by a recessive allele (result of a mutation where 3 bases are removed from a DNA molecule) on 1 chromosome |
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sickle-cell disease |
-affects hemoglobin (a protein in red blood cells that carries oxygen) giving his/her red blood cells an unusual sickle shape (genetic disorder)
-the sickle-shaped cells clog blood vessels and cannot carry as much oxygen
-the allele is codominant; 2 alleles = disease; 1 allele = carrier who produces both normal + abnormal hemoglobin, but no symptoms |
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hemophilia |
- a genetic disorder in which a person's blood clots very slowly or not at all, leading to a high risk of internal bleeding
-caused by a recessive allele on the X chromosome |
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down syndrome |
-when a person's cells have an extra copy of chromosome 21
-most often occurs when chromosomes fail to separate properly during meiosis
-results in some degree of mental retardation & heart defects are also common |
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selective breeding |
the process of selecting organisms with desired traits o be parents of the next generation |
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inbreeding |
-a type of selective breeding
-crossing 2 individuals that have similar characteristics/are genetically very similar |
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hybridization |
-another type of selective breeding
-crossing 2 genetically different individuals |
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clone |
an organism that has exactly the same genes as the organism from which it was produced |
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genetic engineering |
the process in which genes from one organism are transferred into the DNA of another organism |
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gene therapy |
a process that involves inserting copies of a gene directly into a person's cells |
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DNA fingerprinting |
DNA from a person's cells are broken down into small pieces/fragments and selected fragments are used to produce a pattern called a DNA fingerprint
(only twins have identical DNA fingerprints) |
