Unit 7 Lesson 6: Gene Expression

Question 1

Body cells all reproduce by the process of

Answer 1

mitosis

Question 2

How do cells replicate

Answer 2

That means that when your cells replicate, they do so by making identical copies of all their genetic material.

Question 3

A parent cell becomes

Answer 3

two identical daughter cells

Question 4

Every cell in your body contains exactly the same genetic information, so how do cells differ

Answer 4

but your cells differ in appearance and function. Your blood cells, for instance, look nothing like your skin cells.

Question 5

What is the state of cells right after mitosis

Answer 5

Just after mitosis, all replicated cells are the same and share the same function.

Question 6

. The increase in number of cells by replication is called

Answer 6

proliferation

Question 7

When cells become more specialized, that is known as

Answer 7

differentiation, or differential gene expression.

Question 8

differential gene expression

Answer 8

the process by which different genes in a cell activate during specialization

Question 9

After mitosis, a cell that is not specialized will undergo what to gcome more specialzied

Answer 9

gene expression

Question 10

gene expression

Answer 10

the process in which instructions in DNA are used to produce a protein or other functional product

Question 11

In molecular biology, the cell cycle is the sequence of events that happen during

Answer 11

cell replication and division.

Question 12

In molecular biology, the cell cycle is the sequence of events that happen during cell replication and division. Describe it. Mitosis, Gap , gap 1. When id synthsis ready to begin

Answer 12

Mitosis (M) in a parent cell results in two genetically identical daughter cells. This is followed by a gap ( G1
) that gives the cell time to rest from replication and grow in preparation for another cycle. When growth is complete, the cell passes the G1
checkpoint, which assures it has reached the correct size to begin synthesis

Question 13

What is sythesis

Answer 13

Synthesis (S), the period in which the cell’s genetic information is copied within its nucleus, begins. Another gap ( G2
) follows, and then mitosis. As mitosis starts, the cell is said to have cycled. This may continue until the cell reaches senescence and loses its ability to replicate.

Question 14

In G0
, the cell leaves the cycle. Why might this happen

Answer 14

This can sometimes happen in order to give a cell a rest period before replication restarts. Cells may also leave the cycle permanently to serve a particular function.

Question 15

terminal differentiation

Answer 15

cells that exit the cell cycle to provide a particular function and can no longer divide

Question 16

what kind of cells are stem cells

Answer 16

Stem cells are undifferentiated cells.

Question 17

What are stem cells able to do

Answer 17

They are able to proliferate and can also give rise to more specialized kinds of cells.

Question 18

A stem cell’s ability to differentiate into certain kinds of specialized cells depends on its

Answer 18

type

Question 19

What may happen when a celll differentiates

Answer 19

When a cell differentiates, it may change in size, shape, and function. Cells change these aspects through gene expression.

Question 20

Think of DNA as your cells’ college course catalog. Elaborate

Answer 20

Every cell will take some courses from the catalog, but very few cells have the ability or need to take all of them. A cell’s function is determined by the portion of DNA that it reads. By turning on or off the parts of the DNA script that are read, stem cells give rise to cells of various functions. On the college campus, all students belong to the college, but they do not all do the same things. Cellular differentiation works in a similar fashion.

Question 21

Totipotent cells

Answer 21

Totipotent cells are the first cells to arise in a developing embryo. They are only present at the beginning of an organism’s development. Think of totipotent cells as students who have just been accepted at a college. The students have not declared a major and can take any course they want. At this college, they aren’t limited to living in the dorms. Totipotent cells are able to differentiate into any cell type the growing embryo needs and may also become extraembryonic (outside of the embryo) placental cells. These cells aid in the development of the embryo and provide functions such as waste removal and providing nutrition.

Question 22

Pluripotent cells

Answer 22

Pluripotent cells are the second type of stem cell to develop in an embryo. Sometimes they are simply called embryonic stem cells. Pluripotent cells are precursors to the tissues that will be formed in a growing embryo. These cells are like students living in the dorms, but they haven’t decided on a major. They might still become anything. A pluripotent cell can differentiate into any cell type within the body but cannot become extraembryonic. This means that these cells cannot fully support the development of the embryo on its own.

Question 23

Multipotent cells

Answer 23

Multipotent cells make up most adult stem cells. Think of them as being like students who have declared their majors, but they can still take many different classes within their fields. A multipotent stem cell can become many different types of specialized cells within a tissue or organ, such as lymphocytes, epithelial cells, or blood cells. In some parts of the body, such as the intestinal tract, multipotent stem cells divide regularly to repair aged or damaged tissues.

Question 24

Oligopotent cells

Answer 24

Oligopotent cells are a class of multipotent stem cells that can become many different types of specialized cell within a tissue or organ, but their ability to differentiate is limited by location. Within the bone marrow, for instance, hematopoietic stem cells differentiate into the different kinds of blood cells, while nonhematopoietic become tissues.

Question 25

oligopotent cells direct meaning

Answer 25

type of multipotent cells that can differentiate into many types of specialized cells but are limited by location

Question 26

A cell’s specific developmental program for specialization is called its

Answer 26

cell fate

Question 27

When does cell fate happen

Answer 27

Cell fate happens when a cell differentiates into a specialized type of cell, such as a liver or muscle cell.

Question 28

what is a expressed gene

Answer 28

A gene segment that is activated to determine a cell’s fate is called an expressed gene

Question 29

What causes a gene to become expressed?

Answer 29

Various environmental factors affect the type of gene expression that occurs.

Question 30

How does temperature affect corrdicles

Answer 30

Temperature, for example, at which crocodile and turtle eggs are incubated determines which sex the embryo becomes.

Question 31

Other environmental factors that have been shown to influence gene expression include:

Answer 31

• pH of the environment
• infection
• nutrition
• light
• oxygen level

Question 32

First step of gene expression transcripation. describe

Answer 32

Transcription – The first step of gene expression occurs within the nucleus. The DNA helix unwinds, and parts of it are transcribed (read) to produce strands of RNA (ribonucleic acid). The new RNA strands contain all the information that the cell will use in differentiation. Though RNA is an exact copy of a DNA section, not all the DNA from a section is always needed for gene expression. After the RNA forms, it goes through a process to remove unneeded (non-coding) DNA and to connect the sections of DNA that will code its differentiation. This process is called splicing. The spliced RNA, ready to control the type of cell differentiation, is called mRNA (messenger RNA). These strands of mRNA then travel out of the nucleus into the cytoplasm.

Question 33

Second step of gene expression translation. describe

Answer 33

Translation – The second step of gene expression usually occurs in the cytoplasm. An mRNA molecule attaches to a ribosome. The ribosomes then make chains of amino acids by translating the information (types and arrangement of molecules) carried by the mRNA. The chains of amino acids are then combined into long strands to form proteins.

Question 34

Thrid step of gene expression folding. describe

Answer 34

Folding – The final step of gene expression is folding of the proteins into complex ribbons and strands. This step is important because without folding the proteins would not be useful in the body. It is the folded proteins that the ribosomes make that determine a cell’s function.

Question 35

Can a cell replicate during differentiation

Answer 35

A cell may be able to replicate itself during differentiation—the process by which less specialized cells become more specialized.

Question 36

What is the role of some differentiated cells

Answer 36

Some differentiated cells repair and maintain body functions.

Question 37

Can all differetinared cells replicate and can all cel profilferate often

Answer 37

Not all differentiated cells are able to replicate, however, and some cannot proliferate often.

Question 38

What does it mena when a cell is in a state of senescence

Answer 38

When a cell is unable to replicate any longer, it is in a state of senescence. In senescence, cellular reproduction stops.

Question 39

When do cells proliferate

Answer 39

Different kinds of cells have different time periods during which they can proliferate.

Question 40

Diufference in senescence in cells

Answer 40

Some cells become senescent almost immediately upon differentiation. Others may proliferate for long periods before senescence sets in.

Question 41

When cells stop proliferating, they are considered to

Answer 41

have left the cell cycle.

Question 42

What does terminal differentiation

Answer 42

A cell that is no longer able to replicate has undergone terminal differentiation.

Question 43

What are examples of body parts that are terminall differentiation

Answer 43

Heart and neural cells are examples of cells that have undergone terminal differentiation.

Question 44

Describe cell activity during the G1 phase and how it relates to mitosis and differentiation.

Answer 44

During the G1 phase, the cell rests from replication while it grows. G1 happens after mitosis but before differentiation. A cell that remains in the cell cycle will continue on to sequencing, and subsequently back to mitosis, while a cell that exits the cycle to begin the G0 phase may then differentiate.

Question 45

Bone marrow cells are considered oligopotent cells and can be transplanted to treat certain types of cancer. Why might bone marrow cells be especially useful for treating certain types of cancer as well as other blood and immune system diseases? Why do you think bone marrow cells might be considered more useful than pluripotent cells?

Answer 45

Hematopoietic cells that can differentiate into any kind of blood cell can more easily replace a diseased blood supply. Nonhematopoietic cells can repair different sorts of damage and allow healthy new growth. Because oligopotent bone marrow cells can become only certain kinds of differentiated cells, they may be more useful than pluripotent cells in which inducing differentiation might leave more chance of error.

Question 46

What is formed during gene expression?

Answer 46

Different types of proteins are formed to initiate gene expression. The type of specialized cells that are produced depends on the type of protein that activates them.

Question 47

In tereating cell damage why doesnt neural stem cells work

Answer 47

Treating cell damage is one of the trickiest parts of medicine. If cell damage causes hearing loss, doctors have traditionally found that loss to be incurable. Neural stem cells hold some promise of helping with cochlear repair, but inducing them to differentiate is difficult and continues to be tested to develop a safe and effective transplant process.

Question 48

How might scienstist use ginkgo biloba to help with cell damage

Answer 48

ginkgo biloba, an extract made from the ginkgo tree, to stimulate new growth of cochlear neural stem cells in mice. The ginkgo biloba leaf contains several unique compounds such as an organic compound called ginkgolide.

Question 49

Ginkgolide A shows

Answer 49

promise as a treatment for inflammation.

Question 50

Ginkgolide B is a component in

Answer 50

migraine remedies and is also used to treat disease relating to the brain and its blood vessels.

Question 51

Ginkgolide C has been shown to im

Answer 51

improve blood flow. Ginkgolide C also is known to protect blood cells from damage.