Author Question: A 41-year-old female with a family history of breast cancer has had a baseline mammogram. She states ... (Read 71 times)

Mollykgkg · **on:** Jun 25, 2018

A 41-year-old female with a family history of breast cancer has had a baseline mammogram. She states that she performs monthly self-breast exams but really has a hard time evaluating her lumps since she has numerous cysts.

At her annual mammogram, the technician views a suspicious area and refers her to the radiologist. She asks the nurse in the office, How can a lump appear so quickly? The nurse's response is based on which of the following principles?
A)
A tumor is undetectable until it has doubled 30 times and contains at least 1 billion cells.
B)
Many tumor cells never leave the M-phase of the cell cycle.
C)
Cancer cells are undifferentiated and come in various shapes and sizes.
D)
If the breast has a lot of cysts, then the fluid within those sacs makes it difficult to feel the hard lumps of a cancer.

Question 2

A researcher is involved in the investigation of an individual's genetic abnormality. Which of the following situations could the researcher most likely rule out as the genetic cause of a mutation?

A)
Loss of a cytosine-guanine base pair
B)
Formation of an adenine-uracil base pair
C)
Substitution of an adenine-thymine base pair for a cytosine-guanine base pair
D)
Insertion of an extra adenine-thymine base pair

AaaA · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

Ans:
A

Feedback:

The ratio of dividing cells to resting cells in a tissue mass is called the growth fraction. The doubling time is the length of time it takes for the total mass of cells in a tumor to double. Tumors do not stay in the M-phase of the cell cycle. Undifferentiated cancer cells do come in various shapes and sizes, but this has nothing to do with the detection of the tumor by palpation. Breast cysts are fluid-filled sacs but are usually not cancerous.

Answer to Question 2

Ans:
B

Feedback:

RNA contains uracil instead of thymine. Formation of an adenine-uracil base pair is a normal event during assembly of messenger RNA.