Cell Differentiation

Which best explains why muscle cells are different from blood cells?

• Muscle cells are produced by the brain, but blood cells are produced by the heart. 
• Different genes are activated in muscle cells than in blood cells. 
• Muscles cells experience different environmental influences than blood cells. 
• A mutation occurs during the development of muscle cells but not in blood cells. 

What is cell differentiation?

• Process by which cells produce more cells
• Process by which cells become specialized
• Process by which cells become unspecialized
• Process by which cells die

What is one goal of cellular differentiation/specialization?

• To create specialized cells to help organism maintain homeostasis.

• To make many cells.

• To make stem cells

• to make single celled organisms

So why do stomach cells function differently than skin cells?

• They have different DNA.

• Different types of cells simply use different genes contained in the DNA.

Which property is shared by the cells of all living things?

• The cells contain DNA composed of adenine, thymine, guanine, and cytosine.

• The cells are surrounded by a phospholipid bilayer and a cell wall made of cellulose.

• The cells have chromosomes that are located inside a membrane-bound nucleus.

• The cells rely on mitochondria to carry out aerobic cellular respiration.

Which statement best describes a similarity among trees, cats, and amoebas?

• They are prokaryotic organisms.

• They are classified as members of the same kingdom.

• They have genomes that consist of the same number of genes.

• They contain DNA composed of the same four types of nucleotides.

Researchers combined sequences of fruit-fly DNA from a gene for a particular trait with frog DNA. The mixture was heated to separate the DNA strands. Cooling allowed the single strands to form pairs. The researchers observed that some of the fruit-fly DNA paired with frog DNA.

The results provide evidence that —

• similar nucleotides are present in both fruit-fly and frog DNA

• fruit flies and frogs can be made to develop some of the same physical traits

• heat can cause mutations in the DNA sequences of organisms

• the replication of genetic material can occur at any temperature

Which statement BEST describes how genes are expressed in an organism?

• Genes are always off even when resources are available.

• Genes are turned on and off in response to the environment.

• Genes are continuously turned on and off at random intervals of time.

• Genes are on until all the genes have been simultaneously expressed.