DNA and inheritance

9.In a monohybrid cross between two heterozygous parents (Bb × Bb) for a trait where B (dominant) gives round seeds and b (recessive) gives wrinkled seeds, what is the probability of offspring having wrinkled seeds?

10.Which of the following statements about inheritance is true?

11.What technique was used by Rosalind Franklin and Maurice Wilkins to obtain images of DNA?

12.If a dominant allele is present, which trait is expressed?

13.In a species of plant, flower colour is determined by a single gene with two alleles: R (red) dominant and r (white) recessive. If a red-flowered plant with genotype Rr is crossed with a white-flowered plant (rr), what percentage of the offspring are expected to have white flowers?

14.A DNA molecule contains 30% adenine. What percentage of guanine is present?

15.A student extracts DNA from a strawberry and adds it to a test tube containing a solution. A blue dye that binds to DNA is added, and the mixture turns blue. The student then adds an enzyme that breaks down DNA. What colour change would you expect?

16.What is the name of the technique used by Rosalind Franklin and Maurice Wilkins to obtain images of DNA?

17.In a pea plant, the allele for tall stems (T) is dominant over the allele for short stems (t). Two heterozygous tall plants are crossed. What is the probability that a randomly selected offspring will be short?

18.A scientist measures the DNA content of cells from a growing plant. She finds that cells in the root tip have twice the DNA content of cells in the mature leaf. Which explanation is most likely?

19.Which of the following correctly describes the relationship between genes and DNA?

20.How many chromosomes are in a normal human body cell?

21.A student looks at a diagram of DNA and identifies four bases: adenine, thymine, guanine, and cytosine. Which base pairs with cytosine in the double helix?

22.In a breeding experiment, two heterozygous black mice (Bb) are crossed. Black fur (B) is dominant over white fur (b). The offspring are counted: 12 black and 4 white. How does this ratio compare to the expected ratio?

23.What shape did Watson and Crick discover that DNA has?

24.A family has three children. The parents both have brown eyes (a dominant trait), but one child has blue eyes (recessive). Which statement is correct?

25.A student uses a technique to separate DNA fragments by size. Which technique is most likely being used?

26.In a DNA extraction experiment, a student adds cold ethanol to the mixture. What is the purpose of the cold ethanol?

27.A scientist crosses a pea plant that is homozygous dominant for tall stems (TT) with a pea plant that is homozygous recessive for short stems (tt). All offspring are tall. The scientist then crosses two of these offspring. What proportion of the second-generation offspring will be short?

28.Which of the following is the correct order of structures from smallest to largest?

29.A scientist uses a radioactive probe that binds to a specific DNA sequence. This technique is used to identify a gene. What is this technique called?

30.The diagram shows part of a DNA molecule. Which labelled part represents a nucleotide?

31.Who produced the famous 'Photo 51' that helped determine the structure of DNA?

32.Which of the following statements is false?

33.A scientist wants to amplify a small sample of DNA for analysis. Which technique should she use?

34.In a breeding experiment, two heterozygous black mice (Bb) are crossed. Black fur (B) is dominant over white fur (b). The offspring are counted: 12 black and 4 white. How many of the black mice are expected to be heterozygous?

35.A student adds protease to a mixture during DNA extraction. What is the purpose of adding protease?

36.How many chromosomes are in a typical human body cell?

37.The structure of DNA is described as a:

38.Which of the following statements is true?

39.A recessive trait will only be expressed if:

40.The diagram shows a DNA molecule. Which labelled part represents a nucleotide?