Unit 6 Lesson 4: Gene Expression Flashcards
What is Gene expression
Gene expression is the process by which genetic information from a gene is used to make a protein.
What is a gene
a section of DNA that eventually translates into a protein
What would the human body without protein look like
Without proteins, your body wouldnât be able to support your muscles or major organs. In fact, your organs might not exist because they require proteins to perform their functions.
What is out outward apperance determined by
Even the outward appearance of an organism is determined by its genes.
What does the P protein control
For example, one protein, called the P protein, controls how special cells in the eye produce and store melanin, which determines eye color.
What determines the color of eyes
Brown eyes are caused by more melanin production while blue eyes have less.
What are essential for your body to function
proteins and enzymes
Where are the instructions to make protein written
and stored
he instructions to make proteins are written and stored in nucleic acids. You know these macromolecules as DNA and RNA.
What is protein synthesis
. Protein synthesis is the process during which cells make proteins.
What is the first step of orotein sythesis, what provides the code for protein
s. Recall that DNA is transcribed into mRNA in the first step of the process and that mRNA provides the code for the protein.
What happens to tRNA and codons during protein sythsis? Waht is translation
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.
How is protein formed
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.
How many polypeptide chains are needed for a prtoin to be made
Some proteins require multiple polypeptide chains to come together to form the final protein. Other proteins are made of a single polypeptide chain
. Some proteins also require modifications to become activated. Elaborate
These modifications can include the attachment of certain chemical groups to the amino acids or the removal of certain amino acids.
. Some proteins also require modifications to become activated. Use snakes as an example
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.
How do you know if the protein process si finshed
If the protein will do its work in the cytoplasm, the process is finished.
What happens if the protein will be used in a partficular organelle pr shi[[ed tp the outside of the cell
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.
Do all cells have the same DNA
Each cell has its own purpose and expresses its proteins in different ways and at different times, yet all cells contain the same DNA.
Why do muscle cells nad brain cells have differenct functions
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.
Does a cell make all the proteins coded in its DNA?
The answer is no. That would be a colossal waste of the cellâs energy, so proteins are made only if and when they are needed
What do proteins do
. 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 doesnât activate that gene.
What is central dogma
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.
How does a cell know when to turn a gene on or off?
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.
Gene expression can change over time in response to changing environmental factors as well. An example of this is tawny owls. Elaborate
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.
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?
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.
What is a mutation
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.
How do mutations occur
Mutations can occur through natural events, environmental conditions, or even by artificial means.
What effect do mutations ahve
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.
What is cystic fibrosis
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 (Clâ)
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.
How can mutations be beneficial and necesary for survial
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.
What is a point mutation
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.
