Question

name daniel tello merlas bell dna replication practice

1. for each picture below, describe in a complete sentence what is happening during that step of dna replication.

the dna double helix is unwinding the dna double helix is being separated into two strands two new dna double helix molecules are formed

1. true or false

cytosine, guanine, thymine, and adenine are phosphates
dna is the shape of a helix
a nucleotide is made up of a sugar, phosphate and two nitrogen bases
replication is performed prior to cell division
adenine always pairs with guanine
complementary base pairing matches up complementary sugars
the sides of a dna molecule are made up of nitrogen bases and sugars
the letters that make up a dna molecule is the code for the genes
replication creates two strands of dna, each with half of the original strand
bases are bonded together to form the steps or rungs of the ladder

1. a. sentence arrange - put the steps of dna replication in order by writing a number in the space before each statement.

two new molecules of dna are created
dna polymerase attach the free - floating nucleotides to the exposed nitrogen bases.
helicase begins to break the hydrogen bonds between nitrogen bases
cell starts into the mitosis phase of the cell cycle.
free floating nucleotides pair up with exposed nitrogen bases.
b. complete the statement
guanine, cytosine, and thymine are the four nitrogen bases
in dna, always forms hydrogen bonds with guanine.
the sequence of carries the genetic information of an organism
the process of produces a new copy of an organisms genetic information
the double coiled shape of dna is called a

Explanation:

• Question 2:
• Cytosine, guanine, thymine, and adenine are nitrogen - bases, not phosphates.
• DNA has a double - helix shape.
• A nucleotide is composed of a sugar (deoxyribose in DNA), a phosphate group, and one nitrogen - base (not two).
• DNA replication occurs before cell division to ensure each new cell gets a complete set of genetic information.
• Adenine pairs with thymine (\(A - T\)), and cytosine pairs with guanine (\(C - G\)).
• Complementary base - pairing only matches up complementary bases (e.g., \(A\) with \(T\), \(C\) with \(G\)), not sugars.
• The sides of a DNA molecule are made of sugar - phosphate backbones, and the rungs are made of nitrogen - bases.
• The sequence of nitrogen - bases in DNA codes for genes.
• DNA replication is semi - conservative, creating two DNA molecules, each with one original strand and one new strand.
• Bases are bonded together (by hydrogen bonds in the double - helix) to form the rungs (steps) of the DNA ladder.
• Question 3a:
• The correct order of DNA replication steps (ignoring the cell - cycle - related incorrect step “Cell starts into the mitosis phase of the cell cycle” which is out of place in the replication process):
• First, helicase breaks the hydrogen bonds between nitrogen - bases to unwind the DNA double - helix.
• Then, free - floating nucleotides pair up with the exposed nitrogen - bases according to base - pairing rules (\(A - T\), \(C - G\)).
• Next, DNA polymerase attaches the free - floating nucleotides (by forming phosphodiester bonds) to form new strands.
• Finally, two new DNA molecules are created.
• Question 3b:
• The four nitrogen - bases in DNA are adenine, guanine, cytosine, and thymine.
• Adenine (\(A\)) always forms hydrogen bonds with thymine (\(T\)), and cytosine (\(C\)) with guanine (\(G\)).
• The sequence of nitrogen - bases in DNA carries the genetic information.
• The process of DNA replication produces a new copy of an organism's genetic information.
• The double - coiled shape of DNA is called a double - helix.

Answer:

• Question 2:
• Cytosine, guanine, thymine, and adenine are phosphates: False.
• DNA is the shape of a helix: True.
• A nucleotide is made up of a sugar, phosphate and two nitrogen bases: False.
• Replication is performed prior to cell division: True.
• Adenine always pairs with guanine: False.
• Complementary base pairing matches up complementary sugars: False.
• The sides of a DNA molecule are made up of nitrogen bases and sugars: False.
• The letters that make up a DNA molecule is the code for the genes: True.
• Replication creates two strands of DNA, each with half of the original strand: True.
• Bases are bonded together to form the steps or rungs of the ladder: True.
• Question 3a:
• Two new molecules of DNA are created: 4.
• DNA polymerase attach the free - floating nucleotides to the exposed nitrogen bases: 3.
• Helicase begins to break the hydrogen bonds between nitrogen bases: 1.
• Free floating nucleotides pair up with exposed nitrogen bases: 2.
• Question 3b:
• The missing words (in order) are: adenine; adenine (\(A\)); nitrogen - bases; DNA replication; double - helix.