chapter 11 review Flashcards
What did Mendel use pea plants to study?
inheritance of traits
What are offspring that result from crosses between parents with different traits called?
hybrids
Why did Mendel take out the male from the flowers of some plants?
so the crosses between plants would be controlled
What did Mendel conclude about how traits are inherited?
that biological inheritance is determined by factors that are passed from one generation to the next. he also concluded that some alleles are dominant and others are recessive
When Mendel crossed a tall plant with a short plant, what did the F1 plants inherit?
an allele for tallness from the tall parent and an allele for shortness from the short parent
What does the principle of dominance state?
that some alleles are dominant and others are recessive
When Mendel crossed true-breeding tall plants with true-breeding short plants, why were all the offspring tall?
the allele for tallness is dominant
What can the principles of probability be used for?
predict the traits of the offspring produced by genetic crosses
If a heterozygous tall pea plant is crossed with a short plant, what is the probability that a F1 plant will be tall?
50%
What name is given to an organism that has two identical alleles for a particular trait?
homozygous
What does a punnett square show?
the possible genotype outcomes for the offspring
What principle states that during gamete formation genes for traits separate without influencing each other’s inheritance?
principle of independent assortment
Situations in which one allele for a gene is not completely dominant over another allele for that gene are called what?
incomplete dominance
How many different allele combinations would be found in gametes produced by a pea plant whose genotype was RrYY?
2
What type of inheritance produces offspring with two dominant traits?
codominance
What is variation in human skin color an example of?
polygenic traits
What do Mendel’s principles of genetics apply to?
all organisms
Why did Thomas Hunt Morgan use fruit flies in his studies?
fruit flies produce a large number of offspring
What symbol represents the number of chromosomes in a gamete?
N
How are organism’s diploid number and haploid number related?
the diploid number is half of the haploid number
What process produces gametes?
meiosis
What happens in crossing-over?
homologous chromosomes pair up with each other and exchange different segments of their genetic material to form recombinant chromosomes
When do chromosomes form tetrads?
prophase I
What happens or doesn’t happen between meiosis I and meiosis II that reduces the number of chromosomes?
the DNA doesn’t copy
How are the results of mitosis different from the results of meiosis?
mitosis results in 2 daughter cells and meiosis results in 4 sex cells
What assorts independently?
chromosomes
What are gene maps based on?
the frequency of crossing-over between genes
How many recessive alleles must be inherited to show the recessive trait?
2
How many sets of chromosomes are in a diploid cell?
2
When you flip a coin, what is the probability that it will come up tails?
50%
What can the principles of probability be used for?
predict the traits of the offspring produced by genetic crosses
If a heterozygous tall pea plant is crossed with a short plant, what is the probability that an F1 plant will be tall?
50%
What name is given to an organism that has 2 identical alleles for a particular trait?
homozygous
What does a Punnett square show?
the possible outcomes for genes of an offspring
What principle states that during gamete formation genes for traits separate without influencing each other’s inheritance?
principle of independent assortment
Situations in which one allele for a gene is not completely dominant over another allele for that gene are called what?
incomplete dominance
How many different allele combinations would be found in gametes produced by a pea plant whose genotype was RrYY?
2
What type of inheritance produces offspring with two dominant traits?
codominance
