A weight gain of 11-18 pounds doubles the risk for

n the Meselson-Stahl DNA replication experiment, if the cells were first grown for many generations in 15N containing media, and

nirvana33 [79]

Answer:

50%

Explanation:

DNA replication is a semi-conservative process. It means that after DNA replication, the newly formed DNA molecules have one parental strand and one newly formed strand. The cells in the experiment have DNA with 15N. After one round of DNA replication, each DNA molecule would have one parental DNA strand with 15N and one newly formed DNA strand with 14N.

However, after the second round of DNA replication, each hybrid DNA with strand having 15N and the other with 14N would be unwound. The parental heavy DNA strands would be present in the 50% of the newly formed DNA while the rest 50% of DNA molecules would have both strands with 14N (both light strands).

5 0

2 years ago

Antibodies are composed of two types of peptides, heavy chains and light chains. One of the major classes of antibody molecules

timurjin [86]

Answer and Explanation:

a. form the antigen-binding site ⇒ both chains

The antigen-binding site is formed by one hypervariable region of the light chain (VL) and one hypervariable region of the heavy chain (VH). So, both type of chains contributes to antigen recognition.

b. contain multiple variable domains ⇒ none

Both chains - light and heavy - contain <u>only one</u> variable domain (VL and VH).

c. are found in the Fab fragment ⇒ both chains

The Fab fragment is composed of portions of both light and heavy chains: each portion contains one variable domain and one constant domain. The Fab fragment binds specifically the antigen.

d. are found in the FC fragment ⇒ heavy chains

The Fc region is composed of portions of heavy chains (CH² and CH³), so it contains constant domains.

e. contain only one constant domain ⇒ light chains

Each light chain contains one variable domain (VL) and one constant domain (CL).

f. contain multiple constant domains ⇒ heavy chains

Each heavy chain contains three constant domains: CH¹, CH² and CH³.

g. contain only one variable domain ⇒ both chains

Both light and heavy chains contain one variable domain. The difference is given by the number of constant domains: light chains have 1 constant domain while heavy chains have 3 constant domains.

8 0

2 years ago

20. Explain how health care professionals treat unregulated (or abnormal) cellular growth in the body

goldenfox [79]

Unregulated and uncontrolled cell growth is the most common simple definition of cancer. Because of the many types of cancers and a huge range of possible symptoms, treatments are also very diverse. Type of treatment also depends on cancer stage at diagnosis, and the patient's overall health. Some forms of treatment:

• Chemotherapy-usage of chemicals (medications) that target rapidly uncontrolled dividing cells,

• Hormone therapy

• Immunotherapy-usage of the medications that boost the immune system

• Radiation therapy-usage of radiation to kill the cancer cells

• Surgery

• New approaches such as stem cell therapy or personalized therapy.

8 0

2 years ago

In this lab, the three flocks of birds changed in numbers between generation 1 and generation 3. Why? Check all reasons. The amo

anyanavicka [17]

Working in a lab means working under controlled environment. If in the generation 1 and generation 3, the number of bird’s increases or decreases in number, the possible conditions for this would

- The amount of food increased or decreased

- If a flock’s beak type made it easier to pick up the available food, the flock grows and vice versa

Justification: if the beak type for generation 1 makes the food intake easier, it will grow which ultimately decreases the food for the generation 3 which has un-supportive beak type.

9 0

2 years ago

Read 2 more answers

Based on the model explain whether the molecules shown crossing the membrane require energy to do so

Svetach [21]

Answer:

As the diagram is not given, hence let's generally describe the movement of molecules along the cell membrane.

Molecules can either pass through the cell without using energy through the process of passive transport. An example includes molecules of oxygen.

Molecules which are large and un-polar cannot move through the cell membrane easily. These molecules will require energy to move through the cell membrane. These molecules might move in with the help of the carrier or facilitated proteins. Examples include molecules of glucose.

4 0

2 years ago