Unit 6 Lesson 4: Gene Expression

Question 1

What is Gene expression

Answer 1

Gene expression is the process by which genetic information from a gene is used to make a protein.

Question 2

What is a gene

Answer 2

a section of DNA that eventually translates into a protein

Question 3

What would the human body without protein look like

Answer 3

Without proteins, your body wouldn’t be able to support your muscles or major organs. In fact, your organs might not exist because they require proteins to perform their functions.

Question 4

What is out outward apperance determined by

Answer 4

Even the outward appearance of an organism is determined by its genes.

Question 5

What does the P protein control

Answer 5

For example, one protein, called the P protein, controls how special cells in the eye produce and store melanin, which determines eye color.

Question 6

What determines the color of eyes

Answer 6

Brown eyes are caused by more melanin production while blue eyes have less.

Question 7

What are essential for your body to function

Answer 7

proteins and enzymes

Question 8

Where are the instructions to make protein written
and stored

Answer 8

he instructions to make proteins are written and stored in nucleic acids. You know these macromolecules as DNA and RNA.

Question 9

What is protein synthesis

Answer 9

. Protein synthesis is the process during which cells make proteins.

Question 10

What is the first step of orotein sythesis, what provides the code for protein

Answer 10

s. Recall that DNA is transcribed into mRNA in the first step of the process and that mRNA provides the code for the protein.

Question 11

What happens to tRNA and codons during protein sythsis? Waht is translation

Answer 11

During protein synthesis, specific tRNA molecules attach to the codons in the newly formed mRNA to bring specific amino acids to the mRNA during a process called translation.

Question 12

How is protein formed

Answer 12

In order to form a protein, amino acids within the polypeptide chain interact with one another to fold the chain into a specific shape. This shape determines the function of the protein.

Question 13

How many polypeptide chains are needed for a prtoin to be made

Answer 13

Some proteins require multiple polypeptide chains to come together to form the final protein. Other proteins are made of a single polypeptide chain

Question 14

. Some proteins also require modifications to become activated. Elaborate

Answer 14

These modifications can include the attachment of certain chemical groups to the amino acids or the removal of certain amino acids.

Question 15

. Some proteins also require modifications to become activated. Use snakes as an example

Answer 15

For example, in snakes, venom is a protein, but to protect the snake, it is initially made in an inactive form. Just as it is being injected into the prey, enzymes cut off part of the venom protein, making it active.

Question 16

How do you know if the protein process si finshed

Answer 16

If the protein will do its work in the cytoplasm, the process is finished.

Question 17

What happens if the protein will be used in a partficular organelle pr shi[[ed tp the outside of the cell

Answer 17

If the protein will be used in a particular organelle or shipped to the outside of the cell, two cell organelles, the endoplasmic reticulum and Golgi apparatus, take care of processing and shipping the protein to its destination.

Question 18

Do all cells have the same DNA

Answer 18

Each cell has its own purpose and expresses its proteins in different ways and at different times, yet all cells contain the same DNA.

Question 19

Why do muscle cells nad brain cells have differenct functions

Answer 19

For example, muscle cells and brain cells have different shapes and characteristics. Muscle cells contract and brain cells transmit messages. They can have different functions because they transcribe different parts of the DNA sequence.

Question 20

Does a cell make all the proteins coded in its DNA?

Answer 20

The answer is no. That would be a colossal waste of the cell’s energy, so proteins are made only if and when they are needed

Question 21

What do proteins do

Answer 21

. Proteins regulate many functions in the body including contracting muscles to move bones, producing gastric juices to digest food, and producing melanin that gives your skin a dark color to protect you from ultraviolet, or UV, light.
A muscle cell has no use for melanin, so it doesn’t activate that gene.

Question 22

What is central dogma

Answer 22

A major principle of molecular biology, called the central dogma, is that genetic information flows from DNA to RNA to create functional proteins that result in the traits of an organism.
DNA nucleotide sequences code for these proteins, which are the key to gene expression.

Question 23

How does a cell know when to turn a gene on or off?

Answer 23

Some genes are turned on, or activated, by the presence or absence of certain substances in the cell. Genes can be turned off, or repressed, by noncoding segments, segments of DNA that do not code for proteins. These noncoding segments repress gene expression by blocking the transcription of the gene.

Question 24

Gene expression can change over time in response to changing environmental factors as well. An example of this is tawny owls. Elaborate

Answer 24

Tawny owls can be either brown or a grayish-brown color. Tawny owls live in areas that have snowy winters and the grayish-brown color helps them blend into the snow. By blending into the snow, they can be camouflaged which allows them to be better hunters. But since the overall temperature on earth is rising, the winters in the areas they live in are less snowy. Over several generations, this has caused less grayish-brown owls to be born and more brown owls to be born. The brown owls can camouflage better in the environment when there is not snow, so more brown owls then grayish-brown owls are able to survive and reproduce.

Question 25

If DNA holds the code for proteins that perform various functions throughout the body, what would happen if that code was missing a base, had an extra base, or had the wrong base?

Answer 25

Think about how a message could be changed if a few words were misspelled or were out of place. These variations in the code can occur during DNA replication when the DNA molecule is copied. They can also occur during transcription when the DNA code is being copied into mRNA. . Bases could be inserted incorrectly or could be skipped, causing a mutation.

Question 26

What is a mutation

Answer 26

a random change in the sequence of nucleotides in DNA or RNA/ A mutation is a change in the genetic information that can affect the production of proteins and in turn, gene expression.

Question 27

How do mutations occur

Answer 27

Mutations can occur through natural events, environmental conditions, or even by artificial means.

Question 28

What effect do mutations ahve

Answer 28

Many mutations have little or no effect on gene expression. However, some mutations can be harmful and can dramatically alter the way a protein functions.

Question 29

What is cystic fibrosis

Answer 29

cystic fibrosis is an inherited disorder. It is caused by a mutation in which three bases have been deleted from the CFTR gene. The deletion of these bases results in a change in the structure of a single protein. This protein is located in the membrane surrounding every cell in the body and is needed to carry chloride ions (Cl−) across the membrane to the cells of essential organs. Without chloride ions, water and thick mucus build up in the lungs, making breathing difficult and increasing the risk of infection. The mucus buildup also prevents the release of digestive enzymes from the pancreas into the intestines. Without digestive enzymes, the body cannot absorb essential nutrients, which could lead to malnutrition, stunted growth, and other health issues.

Question 30

How can mutations be beneficial and necesary for survial

Answer 30

For example, many adult humans cannot digest the sugar lactose, which is present in milk and milk products. A mutation that allows a person to break down lactose to yield energy would be beneficial in populations that raise cows, sheep, and goats. This mutation could help to feed people who live in food- or nutrient-scarce areas.

Question 31

What is a point mutation

Answer 31

Most mutations involve a change in a single base. These mutations are known as point mutations because a change occurs at a single point along the DNA sequence.

Question 32

When does a point mutation occur

Answer 32

Typically, a point mutation occurs during DNA replication and is then passed on to a newly created cell during mitosis.

Question 33

When does a subsitution mutation occur

Answer 33

. Substitution mutations occur when one base in a gene is replaced with another base.

Question 34

What does substituion mutation affect

Answer 34

This mutation usually affects only one base, and thus one amino acid in the protein structure.

Question 35

There are three types of substitution mutations:

Answer 35

silent, missense, and nonsense.

Question 36

What is a silent mutation

Answer 36

A silent mutation is the result of a change in a base in the DNA that has no effect on the amino acid sequence in the protein.

Question 37

Why does a silent mutation have no effect

Answer 37

Since the amino acids remain unchanged, this mutation has no effect on the protein function.

Question 38

What is a missense mutation

Answer 38

a type of substitution mutation in which the change in the DNA sequence changes the amino acid in the protein

Question 39

What is a nonsense mutation

Answer 39

a type of substitution mutation in which the change in the DNA sequence changes the mRNA codon to a stop codon

Question 40

What does the severtiy of subsistuiton mutation depend on

Answer 40

The severity of substitution mutations depends on what exactly changes about the protein.

Question 41

What effect do silent mutations have

Answer 41

no effect

Question 42

What effect do missense mutations have

Answer 42

With missense mutations, it depends on the amino acid that is changed.

Question 43

When will missense mutations ahve little affect

Answer 43

ome amino acids have similar chemical properties, so changes involving amino acids with similar chemical properties can have very little effect on the protein.

Question 44

What is sickle cell anemia (a type of missense mutation

Answer 44

sickle cell anemia, which is a disease that involves a protein in red blood cells, dramatically alters how the protein functions within red blood cells and can result in the death of the individual.

Question 45

What does the affect of nonsense mutations depend on

Answer 45

. Finally, nonsense mutations, like missense, depend on where the mutation happens.

Question 46

When will a nonsense muation have the most effect

Answer 46

If the mutation happens near the beginning of the mRNA, then many amino acids will be affected, which could have a huge impact on the function of the protein. I

Question 47

When does a nonsense mutaiton have little effecrt

Answer 47

If the nonsense mutation happens closer to the end of the protein, it’s possible that this may have very little effect.

Question 48

Why are deletions and insertions more serious

Answer 48

Deletions and insertions are more serious because a large part of the DNA is affected.

Question 49

what kind of mutations are deletions and insertions

Answer 49

frameshift mutations

Question 50

What are frameshift mutation

Answer 50

a change in DNA that shifts the reading of the genetic message

Question 51

What is the genetic code

Answer 51

Recall that the genetic code is read in groups of three bases, called codons in mRNA.

Question 52

When does deletion occur

Answer 52

Deletion occurs when one base is removed, and it affects the remainder of the amino acid sequence in the protein.

Question 53

what is deletion

Answer 53

a type of mutation that involves one or more bases being deleted from the DNA sequence

Question 54

Use a sentence that demonstarates deletion

Answer 54

Consider the sentence: The cat ate the rat. Image that you must read this sentence three letters at a time. If the c is deleted, the sentence will be read as: The ata tet her at. Notice how everything past the mutation is affected because of how the reading frame was shifted. The sentence becomes meaningless.

Question 55

What affect does insertion ahve

Answer 55

Insertion also affects a large portion of the amino acid sequence of a protein because it adds an additional base to the DNA sequence.

Question 56

What is insertion

Answer 56

a type of mutation that involves one or more bases being added to the DNA sequence

Question 57

Use a sentence that describes insertion

Answer 57

Think of the sentence: The cat ate the rat. Insert the letter t, and the sentence will be read as: The cat tat eth era t. You can see how a gene would be greatly affected by a deletion or insertion, especially if these mutations occur near the beginning of the protein.

Question 58

when do chromosomal mutations occur

Answer 58

Chromosomal mutations occur when the structure of a chromosome is altered. Pieces of chromosomes are sometimes lost or duplicated during cell division.

Question 59

What are the types of chromosomal mutations

Answer 59

For example, part of the chromosome may be lost, resulting in loss of one or more genes. Part of a chromosome may be repeated, resulting in a duplication of one or more genes. Or a segment of a chromosome may be lost from one chromosome and inserted into another chromosome, a mutation called a translocation. Finally, part of the chromosome can be inverted such that the order of the genes is reversed.

Question 60

What is inversion chromosomal

Answer 60

Broken chromosome parts joins it again but it is turned 180 degree

Question 61

What is translocation in chromsomes mutations

Answer 61

Non-homologous chromosomes exchange segements

Question 62

Protein synthesis is the process of making proteins using the instructions embedded in DNA. Based on what you’ve learned in this narrative, what are the steps of protein synthesis?

Answer 62

* DNA us transcribed into mRNA * mRNA is translated into amino acids * Amino acids form a chain * THe amino acid chain is folded into protein in the endoplascmic reticulm In protein synthesis, DNA is first transcribed into mRNA. This mRNA is then translated into amino acids. The amino acids form a chain and this chain is folded into the protein in the endoplasmic reticulum.

Question 63

All cells make all the proteins encoded in their genome all at once. Is the statement true or false?

Answer 63

false; each type of cell makes a specfic set of proteins

Question 64

Explain how the nucleotide sequence of your DNA determines your eye color?

Answer 64

Nucleotide sequences code for proteins. If your DNA code results in a low amount of melanin in your eye, you will have blue eyes. If it results in a higher amount of melanin to be produced, you will have brown eyes.

Question 65

Based on what you’ve learned about gene expression, research and explain the role of a digestive enzyme that is produced only when you start eating food.

Answer 65

Any digestive enzyme produced by the stomach or pancreas is correct. Students should discuss what macromolecule their particular enzyme digests. For example, pepsin produced by the stomach digests proteins.

Question 66

Why is it important that some genes are expressed at times and not expressed at other times?

Answer 66

Many genes do not need to be expressed all the time because the proteins they code for are not needed. Gene expression is only activated when the protein is needed. This conserves energy and resources in a cell.

Question 67

” Based on what you’ve learned so far about the relationship between DNA and protein, speculate on what introns and exons are.

Answer 67

Introns are noncoding sections in DNA. Exons contain the codes for proteins.

Question 68

what happens to the protein if a change occurs before the start or after the stop signal?

Answer 68

No change happens to the protein because the sections before the start signal and after the stop signal do not code for protein.

Question 69

Can you think of a way for scientists to test the relationship between a gene and a protein?

Answer 69

Inactivate the gene and see if the protein is still being made by the cell.

Question 71

How can scientists test the relationship between a protein and a trait? How can the scientist be sure that the relationship is causal and not just a correlation?

Answer 71

Student answers should discuss disabling a certain protein and observing any changes in the organism’s traits. To make sure that the change is causal and not correlation, the student should discuss instances where a trait is altered but the protein in question has not been disabled.

Question 72

Genetic variation can change for many reasons. One of them is climate change elaborte

Answer 72

Climate change is caused by the increased amount of carbon dioxide in the atmosphere from people driving vehicles, operating factories, and using electricity. This has caused the overall temperature on earth to increase. This increase in temperature is causing many organisms in a species to die, changing which genes are passed on and which are n

Question 73

What were tawny owls like

Answer 73

Since tawny owls live in places that get a lot of snow, it is more beneficial for them to have a lighter, grayish-brown coat color. This helps them camouflage against the snow and be less visible to other animals. Tawny owls can also be a deeper brown color. This helps them camouflage against brown tree trunks when it is not snowy.

Question 74

What are tawny owls like now

Answer 74

In less snowy conditions, owls with a brown coat that can camouflage against tree bark will have a better chance of surviving. This means that the grayish-brown tawny owls will be the ones who die. So, the brown coat trait will be passed down more than the grayish-brown coat trait. Therefore, more owls will be brown than grayish brown.

Question 75

Genes are turned into proteins. What do proteins determine?

Answer 75

The traits of an organism.

Question 76

What is an impact of climate change?

Answer 76

Rising temperatures

Question 77

What are two coat colors of the tawny owl?

Answer 77

Brown and grayish-brown

Question 78

Why does the coat color of tawny owls matter?

Answer 78

It helps them camouflage and hide from other animals.