Ch 4 Sect. 3&4: Cell and Inheritance/ DNA Connection
What are three possible effects of mutations?
1. Harmful 2. Helpful 3. Neutral (neither harmful nor helpful)
When chromosomes fail to separate properly during meiosis, what are the three possible results?
1. too many of a chromosome in cells 2. too few a chromosome in cells 3. or extra segments of a chromosome in cells
How many chromosomes does each human egg cell contain?
23 chromosomes
How many chromosomes does each human sperm cell contain?
23 chromosomes
What happens during the process of fertilization?
23 chromosomes in a sperm cell join the 23 chromosomes in an egg cell
How many pairs of chromosomes does each human body cell contain?
23 pairs
How many major differences are there between DNA and RNA?
3
What are the rungs of the DNA ladder made up of?
4 different bases- Adenine, thymine, guanine, and cytosine
How many chromosomes does a zygote have?
46 chromosomes
How many chromosomes does each human body cell contain?
46 chromosomes
Explain how a chromosome come to exist in pairs.
Chromosomes exist in pairs with 1/2 of the chromosomes being inherited from the male parent and 1/2 from the female parent
What are chromosomes mostly made of?
DNA
What are TWO processes in which mutations can occur?
DNA replication process & During Meiosis
What came from the single cell that formed during fertilization?
Every one of the trillions of cells in the human body
what does the Chromosome Theory of Inheritance state?
Genes are carried from parents to their offspring on chromosomes
What does a help mutation do?
Improves an organism's chance for survival and reproduction
How do the amino acids line up?
In a chain
What are the two major types of RNA?
Messenger RNA, Transfer RNA
How many strands does RNA have?
One
Where does each chromosome in the pair come from?
One chromosome comes from the male parent, the other comes from the female parent
What does a harmful mutation do?
Reduces the organisms chance for survival and reproduction
Contrast the number of chromosomes in sex cells with the number of chromosomes in body cells.
Sex cells have half the number of chromosomes as body cells
What does transfer RNA carry?
Specific amino acids
What are three types of mutations that can occur in the DNA replication process?
Substitution of nitrogen bases in a sequence Deletion of nitrogen bases in a sequence Addition of nitrogen bases in a sequence
What happens if a mutation occurs in a sex cell?
The mutation can be passed on to an offspring and effect the offsprings phenotype
What happens if a mutation occurs in a body cell?
The mutation will not be passed on the organisms offspring
What does the order of the three-letter codes on messenger RNA determine?
The order of the amino acids in the chain
If a mutation is neither helpful or nor harmful, what does the determination often depend on?
The organisms environment
What do proteins help determine?
The size, shape, color, and many other traits of an organism
What nitrogen base is present in DNA but not in RNA?
Thymine
How many strands does DNA have?
Two
What nitrogen base is present in RNA but not it DNA?
Uracil
When messenger RNA is produced, what is the exception?
Uracil (instead of thymine) pairs with adenine
Who was the American geneticist who studied the cells of grasshoppers and formulated the Chromosome Theory of Inheritance?
Walter Sutton
When often occurs during meiosis to cause a mutation?
When chromosomes don't separate correctly
Can an organism be heterozygous for some traits and homozygous for other traits
Yes
Define Mutation
a change in a gene or chromosome
What forms because of the order of the nitrogen bases?
a genetic code that specifies what protein will be produced
Where is a gene located?
a specific place on a chromosome
What does each gene control?
a trait
What does a zygote contain?
all of the information needed to produce a new human being
How does the protein chain grow?
as each amino acid is added
How are the genes lined up on both chromosomes in a pair?
in the same order on both chromosomes
What are proteins?
long-chain molecules made of individual amino acids
What are the sides of the DNA ladder made up of
molecules of deoxyribose ( a sugar) alternating with molecules of phosphates
Depending on which sperm cell combines with which egg cell, what happens?
one of the allele combinations shown in the Punnett Square boxes will result
What does a group of three DNA bases code for?
one specific amino acid
What is protein synthesis?
process in which the cell uses information from a gene on a chromosome to produce a specific protein. It takes place on the ribosomes in the cytoplasm of a cell
What can a mutation cause a cell to do?
produce an incorrect protein during protein synthesis
What is a gene?
section of a DNA molecule that contains the information to code for one specific protein
What type of molecule is different in DNA and RNA?
sugar
What happens during Meiosis?
the chromosome pairs separate and are distributed to two different cells
What does a Punnett Square show?
the events that occur during Meiosis
Define Meiosis
the process that occurs in the formation of sex cells (sperm and egg) by which the number of chromosomes is reduced by half
As a result of meiosis, what happens to the sex cells?
the result of sex cells have only half as many chromosomes as the other cells (body cells) in the organism
What is the main function of genes?
to control the production of proteins in an organism's cells
Define transfer RNA (tRNA)
type of RNA in the cytoplasm that carries an amino acid to the ribosome and adds it to the growing protein chain.
Define messenger RNA (mRNA)
type of RNA that copies the coded message from the DNA in the nucleus and carries the message to the ribosome in the cytoplasm
What does the order of amino acids determine?
which protein will be formed
What is a fertilized egg cell called?
zygote
