TEAS Science- Chromosomes, genes, and DNA

Mitochondria

A small amount of DNA is found

Which of the following defines a codon? A. A triplet of bases that codes for an amino acid B. A triplet of amino acids that codes for a base C. A triplet of genes that code for a protein. D. A tRNA with an amino acid hooked to it

A. A triplet of bases that codes for an amino acid- A codon is three bases in a row that code for an amino acid

Which of the following best describes the packaging of DNA in a cell from the smallest unit to the larges? A. Nucleotides-DNA-Chromosomes-genome B. DNA-genes-chromosomes-genome C. Genes-chromosomes-DNA-Genome D. Genome-chromosomes-DNA-nucleotides

A. Nucleotides-DNA-Chromosomes-genome- DNA is made of nucleotides, which is packaged into chromosomes; the full set of chromosomes is called a genome

A chromatid is ____ A. A pair of duplicated chromosomes. B. A duplicate in a chromosome pair C. One of 46 molecules of DNA found in a cell nucleus. D. A complementary strand

B. A duplicate in a chromosome pair.- Following replication of chromosomes in a cell, each duplicate in a chromosome pair is called a chromatid

A segment of DNA that contains a word made of three nucleotide is referred to as which of the following? A. Gene B. Codon C. Chromosome D. Genome

B. Codon- A codon is a three-nucleotide "word" that codes for an amino acid

Which of the following are the four nitrogenous bases found in DNA A. Adenine, thymidine, cysteine, guanine B. Cytosine, thymine, adenine, guanine C. Adenoid, cytosine, thymine, guano D. Cytosine, uracil, guanine, thymine

B. Cytosine, thymine, adenine, guanine

What does DNA-->RNA--> Protein mean? A. The complementary strand of bases in a gene is used to make template strand called mRNA which is read by a ribosome to make a chain of amino acids that folds into a protein. B. The Sequence of bases in a gene is used to make an mRNA copy, which is read by a ribosome to make a chain of amino acids that folds into a protein C. The sequence of bases in a gene is used to make an rRNA copy, which becomes part of ribosome where it makes a chain of amino acids that fold into a protein D. The sequence of amino acids in a gene is used to make an mRNA copy, which is read by a ribosome to make a chain of bases that fold into a protein.

B. The Sequence of bases in a gene is used to make an mRNA copy, which is read by a ribosome to make a chain of amino acids that folds into a protein- DNA-->RNA-->Protein is a symbolic way to describe to the process of reading a gene sequence, making an mRNA copy of the gene, which ribosomes use to make a protein

In which of the following directions is DNA coded? A. Left to right B. Top to bottom C. 5' to 3' D. 3' to 5'

C. 5' to 3'- this is how DNA is read

Which of the following statements best describes the DNA helix? A. A twisted ladder with sugars facing each other as the rungs and the phosphates and bases forming the sides of the ladder. B. A twisted ladder with phosphates facing each other as as the rungs and the sugars and bases forming the sides of the ladder. C. A twisted ladder with bases facing each other as the as the rungs and the phosphates and sugars forming the sides of the ladder. D. An extension ladder with sugars facing each other as the rungs and the phosphates and bases forming the sides of the ladder

C. A twisted ladder with bases facing each other as the as the rungs and the phosphates and sugars forming the sides of the ladder.- The Double helix is like a twisted ladder with its sugar-phosphate backbone forming the sides of the ladder and the nitrogenous bases forming the rungs.

Chromosomes are replicated____. A. During the genetic code. B. In mitosis C. In a phase of the cell cycle D. By ribosomes

C. In a phase of the cell cycle- Chromosomes are replicated in a specific phase of the cell cycle

Which of the following statements correctly describes a gene? 1. A gene is a unit of heredity 2. A gene codes for a protein or functional RNA molecule. 3. A gene is equivalent to a chromosome A. Statements 1, 2, and 3 B. Statements 1 and 3 C. Statements 1 and 2 D. Statements 2 and 3

C. Statements 1 and 2- A gene is a unit of heredity, and it encodes a functional molecule.

Chromosome

Contain many genes

Which of the following comparisons is not correct? A. Codons are like words B. Nucleotides are like letters C. Genes are like sentences D. Genes are like words

D. Genes are like words.- Nucleotides are like letters in the language of DNA. Genes are like sentences built from these nucleotide letters. And each gene "sentence" is built of words, known as codons

Where is most of the DNA found in the human neuron? A. Mitochondria B. Cell C. Ribosome D. Nucleus

D. Nucleus- Most of a cells DNA is housed in the nucleus

Dehydration reaction

DNA chain forms a bond with a free nucleotide

Genome

Full set of chromosomes

Mitosis

Is a phase of the cell cycle when replicated chromosomes are separated into opposite ends of a cell just before the cell divides in two.

Cell Cycle

Replication of the chromosomes

Phosphodiester bond

Resulting covalent bond from a dehydration reaction.

Gene

Sections of DNA that code for functional molecules

Codons

Triplets of bases that each code for an amino acid

Proteins

are polymers built of strings of amino acids

Hydrogen Bonds

base to base bonding

DNA

made of nucleotides -is a macromolecule and a polymer

Nucleotides

monomers of DNA- form covalent bonds with one another

Ribosomes

site of protein synthesis