Unit 6 Lesson 3: How Cells Make Proteins

Question 1

Tsar Nicholas II and Tsarina Alexandra of Russia were delighted with the birth of their son Alexei. What did there son have

Answer 1

After his birth, it was soon discovered that Alexei had hemophilia.

Question 2

Why was Hemophila called the royal disease

Answer 2

Hemophilia was once called the “royal disease” because it spread throughout the royal families of Britain, Germany, Spain, and Russia.

Question 3

What does Hemophilia do

Answer 3

The condition prevents blood from clotting normally because it lacks certain blood-clotting proteins called fibrins.

Question 4

What would happen if a person with hemophila cuts themselfs

Answer 4

If a person with hemophilia cuts themself, it can become a life-threatening emergency.

Question 5

DNA

Answer 5

a nucleic acid molecule that contains genes

Question 6

Every cells contains..

Answer 6

DNA

Question 7

What is DNA used for

Answer 7

every cell uses the coded instructions in DNA to make proteins in the same way.

Question 8

What were Alexei’s cells like

Answer 8

Alexei’s cells were unable to make a specific type of protein—the protein that forms blood clots because his DNA did not direct his cells to make the protein.

Question 9

What are proteins

Answer 9

Proteins are large molecules that are composed of smaller molecules called amino acids.

Question 10

What does most of the work in cells

Answer 10

proteins

Question 11

What do proteins do

Answer 11

They make up the structure and are involved in the function of all the body’s tissues and organs.

Question 12

What are enzymes

Answer 12

a type of protein that speeds up chemical reactions

Question 13

What do enzymes control

Answer 13

As enzymes, they control all the metabolic reactions that take place in the body.

Question 14

Waht does every cells contain

Answer 14

every cell of the body contains the codes for making the body’s proteins in its DNA.

Question 15

What acts as a control center for eukaryotic cells

Answer 15

a nucleus is the structure that acts as a eukaryotic cell’s control center because it contains DNA.

Question 16

eukarytic

Answer 16

of a cell type that contains membrane-bound organelles such as a nucleus

Question 17

DNA is packaged into.

Answer 17

Within every nucleus of every cell, the DNA is packaged into threadlike structures called chromosomes.

Question 18

What is a gene

Answer 18

a gene is a segment of a DNA molecule that contains the coded information needed to make a specific protein. One chromosome can contain thousands of genes.

Question 19

Like Alexei, people with hemophilia lack the ability to make the protein they need for their blood to clot; why is that

Answer 19

Like Alexei, people with hemophilia lack the ability to make the protein they need for their blood to clot because the gene that codes for this protein is mutated, or changed, such that it does not code for the protein correctly.

Question 20

The human body suses 20 differnt amino acids to do what

Answer 20

The human body uses 20 different amino acids to form all the proteins it needs.

Question 21

What does protein sythesis involve

Answer 21

Protein synthesis involves both DNA and a different nucleic acid—RNA.

Question 22

RNA is different from DNA in three ways. Elaborate

Answer 22

RNA contains only one strand instead of two, its backbone contains the sugar ribose instead of deoxyribose, and it has the nitrogen base uracil instead of the nitrogen base thymine. If you were to examine a molecule of RNA, you would notice that it appears to be half a DNA double strand, with the single base in each rung exposed.

Question 23

There are 3 types of RNA:

Answer 23

messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). Each type plays a unique role in protein synthesis.

Question 24

What is mRNA

Answer 24

– a nucleic acid that carries the genetic code from DNA to a ribosome

Question 25

Waht is tRNA

Answer 25

a type of RNA molecule that decodes the mRNA sequence into a protein

Question 26

rRNA

Answer 26

a type of RNA, called ribosomal RNA, that is part of the ribosome

Question 27

What type of moelcle is mRNA

Answer 27

mRNA is a messenger molecule.

Question 28

What is mRNAs role

Answer 28

It carries the genetic code from the DNA in a chromosome to ribosomes in the cell cytoplasm. I

Question 29

genetic code

Answer 29

a code used by all known organisms that translates mRNA codons into amino acids

Question 30

ribosome

Answer 30

an organelle that synthesizes proteins

Question 31

Where is mRNA made in eukaryotic cells and prokaroytic cells

Answer 31

In eukaryotic cells, DNA is in the nucleus, so mRNA is made in the nucleus. In prokaryotic cells, which lack a nucleus, mRNA is made from DNA in the cytoplasm.

Question 32

Is mRNA made different depnding on the type of cells

Answer 32

Regardless of the type of cell, the steps for building mRNA are the same.

Question 33

What is the first step in the making of mRNA

Answer 33

First, the hydrogen bond that holds together the two bases in each rung of DNA is broken so the two strands of the desired portion of DNA can unzip and separate. This step exposes the bases in each single strand.

Question 34

What role does RNA polymerase play in the making of nRNA

Answer 34

An enzyme called RNA polymerase if then uses one strand from the DNA as a template to synthesize a messenger RNA molecule. The enzyme does this by bonding complementary bases to the bases in the DNA strand.

Question 35

hydrogen bond

Answer 35

a weak bond that forms between a hydrogen on one molecule and the oxygen, nitrogen, or fluorine of another molecule

Question 36

RNA polymerase

Answer 36

an enzyme involved in making mRNA

Question 37

The process of producing an mRNA molecule from the DNA template strand is known as

Answer 37

transcription.

Question 38

What happens once mRNA is produced

Answer 38

Once the mRNA molecule is produced, it moves to a ribosome in the cytoplasm of the cell, where protein molecules are formed during a process called translation.

Question 39

What is translation

Answer 39

a process that produces a polypeptide chain from mRNA

Question 40

What are ribosomes

Answer 40

Recall that ribosomes are small structures in which proteins are made.

Question 41

What are ribosomes composed of

Answer 41

Ribosomes are composed of two subunits; the large subunit sits on top of the small subunit.

Question 42

Ribosomes are composed of two subunits; the large subunit sits on top of the small subunit. What happens to the mRNA

Answer 42

The mRNA strand moves between these two units, where the information for the protein is read.

Question 43

A sequence of three bases in mRNA is called a

Answer 43

codon.

Question 44

What does each condom speficy

Answer 44

Each codon specifies one amino acid that will be inserted into the protein to be produced.

Question 45

Where are the codons read

Answer 45

These codons are “read” in the ribosome, and the correct amino acids are attached in order to produce the desired protein

Question 46

What determines the sequence of amino acids for the protein that iwll be made

Answer 46

Thus, mRNA provides the code that determines the sequence of amino acids for the protein that will be made.

Question 47

What determines the order of amino acids in the protein

Answer 47

Since the sequence of mRNA is determined by DNA, the sequence of the bases in DNA determines the order of amino acids in the protein.

Question 48

What detrmines the individual amino acids that are addes to the growwing polypeptide chain and what order they are added

Answer 48

The codons in mRNA determine the individual amino acids that are added to the growing polypeptide chain and in what order they are added.

Question 49

polypeptide

Answer 49

a chain of amino acids formed during translation that will fold into a certain shape to make a protein

Question 50

The codons in mRNA determine the individual amino acids that are added to the growing polypeptide chain and in what order they are added.
Why does this happen

Answer 50

This happens because mRNA codons base pair with tRNA molecules. These tRNA molecules are associated with a specific amino acid.

Question 51

Complementary base pairing between mRNA and tRNA is the same as

Answer 51

base pairings in DNA but remember that uracil replaces thymine.

Question 52

How many possilbe codon combinations are there

Answer 52

Because each codon, consists of three bases, there are 64 possible codon combinations (four possibilities for each position).

Question 53

Why is the code redundant

Answer 53

Since there are only 20 amino acids, the code is redundant, meaning that many of these codons produce the same amino acid.

Question 54

When does the polypeptide start and stop

Answer 54

. In addition, there are start and stop codons that direct the ribosome where to start and stop “reading” the mRNA. When the ribosome reaches a stop codon, the polypeptide chain that has been made is complete.

Question 55

What other type of RNA molecule is used in translation

Answer 55

In translation, another type of RNA molecule, called transfer RNA (tRNA) comes into play.

Question 56

What is the size of transfer molecules

Answer 56

Transfer molecules are small.

Question 57

What at the end of the tRNA

Answer 57

One end contains the complementary bases to a codon on mRNA and the other end contains an attachment site for an amino acid.

Question 58

Each amino acid has its own…

Answer 58

Each amino acid has its own unique tRNA

Question 59

When does tRNA attach to a spefic amino acid

Answer 59

Each tRNA molecule attaches to a specific amino acid in the cell’s cytoplasm and carries it to the mRNA strand in the ribosome, where the amino acids are attached in the correct order.

Question 60

The amino acids are joined togeher with what

Answer 60

The amino acids are joined to each other in a polypeptide chain by peptide bonds.

Question 61

What does a stop condon mean at the end of mRNA

Answer 61

A stop codon at the end of the mRNA molecule indicates that the polypeptide is complete and translation should stop.

Question 62

What happens when polypepetide chain is complete

Answer 62

When the polypeptide chain is complete, it detaches from the ribosome.

Question 63

How does maino acid affect shape

Answer 63

These amino acids interact with each other in unique ways to cause the polypeptide to fold into a distinct shape depending on the sequence of amino acids. This folded polypeptide is a protein that will do a very specific function based on its shape.

Question 64

What role does DNA play in forming proteins?

Answer 64

The sequence of bases on the molecule of DNA determines the sequence of codons on the mRNA. The sequence of codons on the mRNA determines the sequence of amino acids in the protein. Therefore, the sequence of bases determines the order of amino acids in the protein.

Question 65

Why is the sequence of nitrogen bases on the mRNA molecule complementary to those on the strand of the DNA molecule that was used as a template?

Answer 65

The mRNA molecule is made of the same bases as the DNA molecule, except that the base uracil, instead of thymine, binds with adenine. Since adenine can only bind with its complementary base, uracil, and cytosine can only bind with guanine, the entire sequence of the mRNA molecule is complementary to the sequence in the DNA strand from which it was copied.

Question 66

What are some differences between DNA and RNA?

Answer 66

There are three important differences between DNA and RNA. DNA has the sugar deoxyribose in its backbones, while RNA has the sugar ribose. DNA has is composed of two strands while RNA has one strand. RNA contains a nitrogen base called uracil instead of thymine.

Question 67

“the structures of the proteins that carry out essential functions in specialized cells are determined by regions of DNA called genes.”

Describe the evidence and reasoning that best supports this claim.

Answer 67

All cells contain the sequence of DNA in a gene that determines the structure of the protein that is to be produced. The function of a protein is determined by its structure, which can be seen in the function of tissues throughout the body. Body tissues are essential for life. Therefore, genes hold the specific code that determines the structure of proteins that perform essential functions throughout the body.

Question 68

Steps cells are made

Answer 68

• DNA zips between the base pairs.
• One of the strands of DNA directs the production of mRNA.
• The strand of mRNA moves to the cytoplasm
• A ribosome attaches tot eh mRNA
• tRNA carries amino acids to the ribsome and attaches it to the mRNa strand
• Amino acids are linked together with poptide bonds

Question 69

Compare and contrast prokaryotic and eukaryotic transcription and translation.

Answer

Answer 69

In prokaryotes, which are cells that do not have a nucleus, both transcription and translation take place in the cytoplasm of the cell. In eukaryotes, which are cells that have a nucleus, transcription takes place in the nucleus while translation takes place in the cytoplasm.

Question 70

There are 64 codons possible because each of the three positions in a codon can have one of four base choices. Would it be possible for a codon to be composed of two bases instead of three? Explain.

Answer 70

No. If a codon consisted of only two bases, there would be four base choices in each of the two positions. Thus, only 16 possible codons would be possible. Since there are 20 amino acids, not all of them could be carried to the ribosome for translation into a protein.

Question 71

What is a mutation

Answer 71

a change in the sequence of bases in a gene; A mutation is any change in the DNA sequence that affects genetic information.

Question 72

Wha tis hemophila caused by

Answer 72

hemophilia is caused by a mutation in the gene that codes for a protein that causes blood to clot.

Question 73

What chromonomes do males and females inheirt form their parents

Answer 73

Males inherit an X chromosome from their female parent and a Y chromosome from the male parent. Females inherit an X chromosome from each parent.

Question 74

For hemopila to be present what must happen

Answer 74

For hemophilia to be present in males, the mutation must exist on their X chromosome. On the other hand, females are affected with hemophilia only if both of their X chromosomes contain the mutation.

Question 75

What do cells do

Answer 75

Cells are little factories that pump out proteins.

Question 76

Do red blood cells ahve genes

Answer 76

Except for your red blood cells, which have no nuclei, all other cells in your body contain your entire set of genes.

Question 77

Except for your red blood cells, which have no nuclei, all other cells in your body contain your entire set of genes. This means that every cell is capable of doing the job of another cell. But that doesn’t happen, does it?

Answer 77

This is due to the fact that each type of cell produces a specific set of proteins. Gene expression is regulated by enzymes called positive and negative transcription factors.

Question 78

What is gene expression regulated by

Answer 78

Gene expression is regulated by enzymes called positive and negative transcription factors.

Question 79

What does transcription factors mean

Answer 79

a class of proteins that regulates transcription in rukaryotes by intereacting with RNA polymerase

Question 80

What does a potive or negative transcription factors mean

Answer 80

As their name suggests, positive transcription factors turn genes on, and negative transcription factors turn genes off.

Question 81

How quickly a cell produces proteins depends on many factors. Elaborate

Answer 81

These factors include the number of enzymes available in the cell, the affinity of RNA polymerase and transcription factors to DNA, and how quickly destroyer enzymes dismantle the mRNA. Sometimes, foreign substances such as chemotherapy drugs can degrade proteins. If these foreign substances enter the cell, it doesn’t matter how much target protein synthesis is produced; the target protein level remains low or non-existent.

Question 82

Is transcription able to start if only one of the positive transcription factors is attached to the DNA?

Answer 82

It depends on the gene. The first gene only required one positive transcription factor, but both positive transcription factors in Gene 2 and 3 must be on the DNA in order for mRNA polymerase to start transcription.

Question 83

If scientists want to find ways to block protein synthesis, is there more than one enzyme that they can target? Explain your answer.

Answer 83

Yes, scientists can target any of the enzymes in protein synthesis to decrease the amount of protein that is being made. Each biomolecule is dependent on the others functioning properly to create the appropriate amount of protein.