remediation 5/25

In one species of plant, red flowers (R) are dominant to white flowers (r). What are the genotypes of the parent plants that are crossed when 50% of the offspring are heterozygous and 50% are homozygous dominant?

• RR x Rr

• Rr X rr

• rr X RR

• Rr X Rr

A biology class is studying the concept of carrying capacity. On a field trip, the students measure a pond and estimate its surface area to be 460 m2. Previous research shows that each frog in a pond requires about 2 m2 of pond space to survive. How many frogs can this pond support?

• 120

• 230

• 920

• 260

Read through the following situations and identify the organelle malfunctioning or primarily affected in individuals with each disorder.

• mitochondria

• Achondrogenesis: Infant has a small body, short limbs and other skeletal abnormalities. Due to serious health problems infants are stillborn or die soon after birth. ABNORMALITIES ARE DUE TO PROTEINS NOT BEING PACKAGED AND MOVED.

• golgi

• Cystic Fibrosis: Thick mucus in the lungs; frequent lung infections; clogged pancreas; digestive problems; salty sweat. SALT HAS PROBLEMS ENTERING AND LEAVING THE CELLS of the lungs and pancreas.

• cell membrane

• Leigh’s Disease: Infants with the syndrome have trouble swallowing, leading to a failure to thrive. This usually occurs after a viral infection. They also become irritable and cry continuously. ORGANS THAT NEED A LOT OF ENERGY like the brain, heart, and intestines WILL BE AFFECTED. Lesions on the brain and brain stem are other symptoms of the disease.

People who have been exposed to excessive radiation often experience mutations. If these mutations only occur in somatic (body) cells, these people may —

• pass on these mutations to their offspring

• experience an increased risk of cancer

• experience difficulties replicating RNA

• develop entirely new DNA sequences in all cells

An important difference between viruses and living cells is that viruses —

• contain more nuclei than cells

• need an energy source by cells do not

• cannot reproduce outside of cells

• cannot mutate but cells can

What is the order of succession shown in this figure?

• A, B, C, D
• B, A, D, C
• C, D, A, B
• D, A, B, C

In mitosis, the two resulting cells are-

• different from the starting cell and identical to each other.

• different from the starting cell and different from each other.

• identical to the starting cell and different from each other.

• identical to the starting cell and identical to each other.