Smartbooks Chapter 4 Flashcards
Which of the following are components of nucleotides? Phosphate groups Nitrogenous bases Sugars (ribose or deoxyribose) Amino acids Proteins
Phosphate groups
Nitrogenous bases
Sugars (ribose or deoxyribose)
In DNA, the base adenine pairs with the base ____
thymine
How many hydrogen bonds do adenine and thymine form with each other?
Two
In the nucleus, DNA is complexed with proteins to form a fine filamentous material called _____
chromatin
In the nucleus of a typical human cell, there are 46 DNA filaments. Which term refers to one of these structures?
Chromosome
Which of the following best describes a histone?
1) A protein component of chromatin that helps to organize and package DNA
2) The pinched spot on the chromosome where two sister chromatids join together
3) A long, noncoding sequence of DNA
4) A segment of the DNA that carries the genetic code for a particular protein
1) A protein component of chromatin that helps to organize and package DNA
When a cell is preparing to divide, it makes an exact copy of all its nuclear DNA. Each chromosome then consists of two parallel filaments called _____ chromatids
sister
How many hydrogen bonds do guanine and cytosine form with each other?
3
Which of the following is true about the centromere?
a) It is what chromosomes attach to, so they can be pulled to the middle of the cell.
b) It is located at the tips of the chromosome “arms”.
c) It is where sister chromatids are joined together.
d) It is a short stretch of DNA wrapped around a cluster of histone proteins.
c) It is where sister chromatids are joined together.
Which term refers to the filamentous material composed of DNA and associated proteins that is found in the nucleus of a cell?
a) Centrioles
b) Chromatids
c) Chromatin
d) Chromosome
c) Chromatin
mRNA is short for ____ RNA
messenger
In the nucleus of a dividing cell, the chromatin condenses so that each _____ is now made of two sister chromatids, can be seen with a light microscope.
chromosome
Histones are \_\_\_\_\_\_. triglycerides proteins carbohydrates nucleic acids
proteins
How are DNA and RNA different?
A) RNA consists of only one nucleotide chain whereas DNA is a double helix.
B) RNA contains a sugar called ribose whereas DNA contains a sugar called deoxyribose.
C) RNA contains adenine, cytosine, thymine and guanine whereas DNA contains adenine, cytosine, thymine and uracil.
D) RNA is much smaller. DNA, by contrast, averages more than 100 million base pairs long.
A) RNA consists of only one nucleotide chain whereas DNA is a double helix.
B) RNA contains a sugar called ribose whereas DNA contains a sugar called deoxyribose.
D) RNA is much smaller. DNA, by contrast, averages more than 100 million base pairs long.
When a cell is preparing to divide, it makes an exact copy of all its nuclear DNA. Each chromosome then consists of two parallel filaments called what? Chromatin Sister chromatids Base pairs Histone groups
Sister chromatids
A(n) ______ is an information-containing segment of DNA that codes for the production of a molecule of RNA, and that in most cases codes for one or more proteins.
gene
A centromere holds \_\_\_\_\_\_\_ together. proteins kinetochores sister chromatids RNA
sister chromatids
Which of the following are true statements about the genetic code?
a) The genetic code relates mRNA codons to protein structure.
b) Each codon in the genetic code can stand for two or more amino acids.
c) The genetic code is expressed as three-nucleotide long sequences called codons.
d) The genetic code allows 20 amino acid to be coded by only 4 different nucleotides.
a) The genetic code relates mRNA codons to protein structure.
c) The genetic code is expressed as three-nucleotide long sequences called codons.
d) The genetic code allows 20 amino acid to be coded by only 4 different nucleotides.
rRNA is short for _____ RNA.
ribosomal
A three-base sequence of mRNA is called a(n) ____
codon
A polypeptide is made of 31 amino acids. What is the minimum number of DNA nucleotides needed to code for this number of amino acids?
93 base pairs
Transcription is the process of copying genetic instructions from a molecule of _____ to mRNA.
DNA
Which of the following statements about codons are true?
The genetic code is expressed as a sequence of codons.
A codon is a three-base sequence of mRNA.
Every codon codes for an amino acid.
A codon is a three-base sequence of tRNA.
The genetic code is expressed as a sequence of codons.
A codon is a three-base sequence of mRNA.
Which term refers to a sequence of three DNA nucleotides that codes for one amino acid?
a) codon
b) base triplet
b) base triplet