ch 5 test Flashcards
who was Gregor Mendel?
an Austrian monk from the 1500 who became famous for his studies in genetics. studied traits in pea plants
why were pea plants such a good choice for his study of genetics?
reproduce quickly, easily observable traits, experimenter can control which pairs of plants reproduce
how can you tell if an organism is true breeding?
plants that produce offspring with the same traits
what is hybrid?
plants produced by a cross between parents with different traits
when Mendel crossed a true-breeding purple plant with a true-breeding white flowered plant, what color were the offspring?
only purple
when he crossed two of the offspring, what color were the flowers in the plants that were produced?
the white flowers reappeared- 75% purple 25% white
what does the x shaped object represent?
a chromosome
in a eukaryotic cell, where would you find these x’s?
in the nucleus
what 2 things make up the x’s
DNA and protein histones
in genetics, what does an uppercase letter represent?
dominant alleles
what does the lowercase letter represent?
recessive alleles
which type of trait can be hidden?
recessive
what is YY?
homozygous
what is Yy
heterozygous
what is incomplete dominance?
(ex.)
neither of the parent’s traits are fully dominant (cow’s hair color)
what is polygenic inheritance?
when multiple genes determine the phenotype
something that might affect the phenotype of an organism
chemicals in the soil
what does DNA stand for
deoxyribonucleic acid
what is the shape of DNA
shaped like a twisted ladder (double helix)
which 2 molecules form the DNA “backbone”
suger and phosphate
what are the bases?
adenine, cytosine, guanine, and thymine
what is replication
when a cell makes a copy of its DNA
describe the steps of a DNA molecule as it replicates itself
it unzips down the middle
new nucleotides are added to build the missing half
the job of DNA is to carry the instructions needed to make
proteins
what happens inside a cell in transcription?
an mRNA strand is made using the instructions in DNA
what happens in translation?
ribosomes use the instructions in mRNA to make a chain of amino acids that form a protein
which organelle reads the instructions in mRNA to make a chain of amino acids that form a protein?
ribosomes
how many bases make a codon
3
give 2 examples of proteins that are made using the instructions in DNA
antibodies
melanin
what is mutation?
a mistake in DNA
3 examples of things that might cause a mutation in DNA
1 chemicals in environment 2 some viruses 3 UV radiation
example of a mutation that would be good for an organism
a change in color that helps an animal camouflage itself
example of a mutation that would be bad for an organism
change in body shape that makes it harder to move
