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HHS Life science
chapter 5
59
Science
7th Grade
11/21/2006

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Term
What is HEREDITY?
Definition
the passing of traits from parents to offspring
Term
Who discovered the principles of heredity?
Definition
Gregor Mendel discovered the principles of heredity while working with pea plants
Term
What is a SELF-POLLINATIING PLANT
Definition
a plant that has both male and female reproductive structures
Term
What is a TRUE-BREEDING PLANT?
Definition
a plant whose offspring will have all of the same traits as the parent
Term
What is CROSS-POLLINATION?
Definition
when pollen from one plant fertilizes the ovules of a flower on a different plant
Term
What is a CHARACTERISTIC?
Definition
a feature that has different forms in a population, like hair and eyes
Term
What is a TRAIT?
Definition
the different forms available for a certain characteristic, like brown, blue, green and hazel for eyes
Term
What are FIRST-GENERATION PLANTS?
Definition
the offspring from crossing two original plants
Term
What is a DOMINANT TRAIT?
Definition
the train that remains in a first-generation plant of parents with different traits
Term
What is a RECESSIVE TRAIT?
Definition
the trait that seems to disappear in a first-generation plant of parents with different traits
Term
What is a RATIO?
Definition
a relationship between two different numbers that is often expressed as a fraction
Term
What ratio did Mendel notice in his second-genereation plants?
Definition
a 3:1 ratio
Term
How did Mendel explain his results?
Definition
He realized that this would only work if each plant had two sets of instructions for each characteristic but donated only one set to each offspring
Term
What are GENES?
Definition
the set of instructions for an inherited trait
Term
What is an ALLELE?
Definition
the different forms that are available for a gene, usually one is dominant and one is recessive (Rr) or (Bb)
Term
How do you show a DOMINANT ALLELE?
Definition
dominant alleles are shown with a capital letter
Term
How do you show a RECESSIVE ALLELE?
Definition
recessive alleles are shown with a lowercase letter
Term
What is a PHENOTYPE?
Definition
the appearance of an organism, physical appearance, how you see them
Term
What is GENOTYPE?
Definition
the entire gentic makeup of an organism; the combination of alleles for a specific trait
Term
What is HOMOZYGOUS?
Definition
when both alleles are the same (RR or rr)
Term
What is HETEROZYGOUS?
Definition
when an organism has one of each allele (Rr)
Term
What is a PUNNETT SQUARE?
Definition
a tool tht is used to organize all of the possible combinatios of offspring for a particular set of parents
Term
What is INCOMPLETE DOMINANCE?
Definition
when one trait is not completely dominant over another (R1, R2)
Term
Why are so many shades of eye color possible?
Definition
at least two different genes affect eye color so many shades of a single color are possible
Term
What are the two types of reproduction?
Definition
asexual and sexual
Term
What is SEXUAL REPRODUCTION?
Definition
when an offspring has two parents and its genotype is not identical to its parent's genotype
Term
What is ASEXUAL REPRODUCTION?
Definition
when an offspring has one parent and its genotype is identical to its parent's genotype
Term
What is PROBABILITY?
Definition
the mathematical chance that something will happen
Term
What are SEX CELLS?
Definition
the parent cells needed for sexual reproduction, they have only one chromosome from each pair of homlogous chromosomes
Term
What are HOMOLOGOUS CHROMOSOMES?
Definition
chromosomes that carry the same sets of genes
Term
What is MEIOSIS?
Definition
the process of cell division that produces sex cells
Term
How is meiosis different from mitosis?
Definition
in mitosis, chromosomes are copied once and the nucleus divides once; in meiosis, chromosomes are copied only once but the nucleus divides twice
Term
What are the results of meiosis?
Definition
one cell produces four new cells and each new cell has only half of the chromosomes of the original cell
Term
What are SEX CHROMOSOMES?
Definition
the pair of chromosomes that determine the sex of an organism
Term
How is the sex of a person determined?
Definition
all egg cells have an X sex chromosome, some sperm cells have a Y sex chromosome and some have an X chromosome; after one egg cell is fertilization by one sperm cell either a X or Y sex chromosome, an XX combination(female) or an XY combination (male) in formed
Term
What is a SEX-LINKED DISORDER?
Definition
when the gene for a disease or disorder is located on the X chromosome
Term
What are some examples of sex-linked disorders?
Definition
1) color-blindness - when you have trouble distinguishing between different colors
2)hemophilia - where a person's blood does not clot correctly
Term
What is a PEDIGREE?
Definition
a tool that traces a trait through several generations of a family
Term
What is SELECTIVE BREEDING?
Definition
when organisms with desirable characteristics are mated to produce offspring with the wanted traits
Term
Gregor Mendel was born in
Definition
Austria
Term
Gregor Mendel did his research
Definition
in a monastery
Term
Both male and female reproductive structures are found in what kind of plants?
Definition
self-pollinating
Term
In Mendel's work, first and second generation mean
Definition
parents and offspring
Term
The offspring of what kind of plants all have the same traits as the parent?
Definition
true breed
Term
One pea plant is able to fertilize another because pea plants can
Definition
cross-pollinate
Term
List two ways that a plant can cross-pollinate.
Definition
animal and wind
Term
Peas can both cross-pollinate and self-pollinate. Why was this a key factor in Mendel's work?
Definition
so he could control what characteristics (traits) the pea plant recieved
Term
In a population, a(n) what is a feature that has different forms?
Definition
characteristic
Term
Different forms of characteristics are called
Definition
traits
Term
Different forms of characteristics are called
Definition
traits
Term
Why was it important to Mendel's work that peas were true breeding?
Definition
when true-breeding plants self-pollinate all of its offspring will have the exact same traits as the parent
Term
How did Mendel make sure that some plants cross-pollinated?
Definition
He removed the arthens of one plant so that the plant could not self-pollinate.
Term
What kind of trait can be seen in the second generation that is not seen in the first?
Definition
recessive traits
Term
Offspring from the first cross of plants is called the
Definition
first-generation plants
Term
What kind of trait can be seen in the first generation?
Definition
dominant trait
Term
What results did Mendel get when he allowed the first-generation plants to self-pollinate?
Definition
every fourth plant had white flowers
Term
When a relationship between two different things is shown as fraction, it is
Definition
a ratio
Term
Gregor Mendel realized the only explanation for his results was that
Definition
each trait had two sets of instructions, one from each parent
Term
Mendel was recognized for his discovery
Definition
more that 30 years later
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