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Science ch. 4

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Heredity
the passing of physical characteristics from parents to offspring
Trait
Each different form of a characteristic, such as a stem height or seed color, is called
Genetics
the scientific study of heredity
Fertilization
when a new organism begins to form when and egg and sperm join
purebread
an organism that has the same alleles
gene
the factors that control a trait
allele(s)
the different forms of a gene
dominant allele
the trait always shows up when the allele is present
recessive allele
the trait is hidden whenever the dominant allele is present
hybrid
an organism that has two different alleles for a trait (Rr)
dominant allele (example)
R
recessive allele (example)
r
probability
the number that describes how likely it is that an event will occur
punnet square
a chart that shows all the possible combinations of alleles that can result from a genetic cross
phenotype
an organism's physical appearance, or visible traits
genotype
an organism's genetic makeup, or allele combinations
homozygous
an organism that has two identical alleles for a trait
heterozygous
an organism that has two different alleles for a trait
codominance
the alleles are neither dominate nor recessive
Chromosome theory of inheritance
genes are carried from parents to their offspring on chromosomes
meiosis
the number of chromosomes is reduced by half to form sex cells, sperm and egg
before meiosis
every chromosome in the parent cell is copied
end of meiosis
four sex cells are produced. each has only half the number of chromosomes that the parent cell had at the beginning of meisos. each cell has only one chromosome from each original pair
chromosomes
these are made up of many genes joined together like beads on a string
DNA ladder
guanine, cytosine, thymine, adenine
RNA ladder
guanine, cytosine, uracil, adenine
during protein synthesis
cell uses information from a gene on a chromosome to produce a specific protein
nitrogen bases
forms a genetic code that specifies what type of protein will be produced
Gregor Mendel
he figured out that if you cross a tall pea plant and a short plant, it will not be medium, the dominant gene will take over
messenger RNA
copies the coded message from the DNA in the nucleas, and carries the message to the ribosome in the cytoplasm
transfer RNA
carries amino acids to the ribosome and adds them to the growing protein
protein synthesis part 1
DNA molecule unzips.
protein synthesis part 2
messenger RNA leaves the nucleus, enters the cytoplasm, and attatches to the ribosome
protein synthesis part 3
transfer RNA attatches to messenger RNA, protein starts to form
protein synthesis part 4
an amino acid is added to the protein chain
mutation
any change in a gene or chromosome. they can cause a cell to produce an incorrect protein
genes
alleles are different forms of
probability
the likelihood that a particular event will occur is called
five chromosomes
If the body cells of an organism have 10 chromosomes, then the sex cells produced during meiosis would have
amino acids, ribosome
during protein synthesis, transfer RNA carries _____ to the ________
CGAAUU
a section of DNA has the base sequence GCTTAA. the corresponding messenger RNA base sequence will be