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							18 Which of these is demonstrated by the information above?

F   The need for controlling variables in experiments

G The need for classifying organisms scientifically

H The importance of predicting trends from scientific data

J   The importance of questioning experimental evidence




19 Part of a DNA strand is represented in the diagram above. In order for DNA to replicate, the strand must
separate at which of the following locations?

F   Between every phosphate-sugar pair

G Between the eight sugar-base pairs

H Between the four nitrogenous base pairs

J   Between any two chemical bonds
20 Which of the following is best supported by the information above?

A Mutations located on chromosome 17 will result in cancer.

B Cancerous growth will cause a mutation in some BRCA1 alleles.

C Mutated BRCA1 alleles are only one factor involved in cancer.

D Women with a mutant allele of BRCA1 will develop cancer.




21 The swordfish has a heat-generating organ that warms its brain and eyes up to 14°C above the
surrounding water temperature. What structures are likely to be found in relatively high concentrations in
the cells of this organ?

A Chromosomes

B Mitochondria

C Nuclei

D Ribosomes




22 A change within a single base pair in DNA is least likely to be observable if the change affects —

A the production of a stop codon

B an unexpressed recessive trait

C actions of a codominant allele

D the expression of a sex-linked trait
23 The diagram shows cell division in which an error has occurred. Which of these statements is most
accurate?

A Cell A lacks the cytoplasm necessary to continue normal cell functions.

B Cell B contains enough genetic material for the cell to reproduce itself.

C Cell A is free of any mutation present in the genetic material of the parent cell.

D Cell B lacks instructions for making the proteins necessary for cell metabolism.




24 Which of these statements describes one possible interaction between the endocrine and respiratory
systems?

F   The heart is composed of muscle tissue.

G Hormones can trigger asthma attacks.

H The rib cage expands to move air into the lungs.

J   Blood cells can attack pathogens.




25 Proteins are produced according to a special code found in the control center of the cell.
Which of these molecules carries this code?

A   DNA

B   ATP

C Glucose

D Lipid