Which one of the following statements is NOT correct ?
- A.Single celled eukaryotes belong to Kingdom Protista
- B.Yeast, a fungus is multicellular
- C.The fungi constitute a unique kingdom of heterotrophs
- D.Ascomycetes, a saprophytic fungi is multicellular or rarely unicellular
Correct answer
Explanation
The correct answer is B, Yeast, a fungus is multicellular. This statement is false, because yeast is one of the few fungi that are unicellular.
In Whittaker's five-kingdom system, fungi form a separate kingdom. Most fungi are made of long thread-like hyphae that form a network called mycelium, but yeast lives as single oval cells that reproduce mainly by budding. Saccharomyces cerevisiae, the baker's and brewer's yeast, ferments sugar into alcohol and carbon dioxide, which is why it is used to make bread rise and to brew alcohol. Yeast belongs to the class Ascomycetes, the sac fungi.
Option A is wrong to pick because the statement is true; Kingdom Protista holds all single-celled eukaryotes such as Amoeba, Paramecium, Euglena and diatoms. Option C is wrong to pick because fungi do form a unique kingdom of heterotrophs; they lack chlorophyll and absorb food as saprophytes, parasites or symbionts. Option D is wrong to pick because Ascomycetes are mostly multicellular, like Penicillium, and rarely unicellular, like yeast.
Exam tip: yeast = unicellular fungus of the Ascomycetes, reproduces by budding; Penicillium = multicellular Ascomycete.
Practice Questions
View allThe valency of phosphorus is
- A.2, 3
- B.3, 4
- C.4, 5
- D.3, 5
Show answer
Phosphorus has five electrons in its outer shell and shows two common valencies, 3 and 5. Phosphorus, atomic number 15, has the electronic configuration 2, 8, 5.
Read the full explanation →Desalination of seawater is done by using reverse osmosis. The pressure applied to the solution is
- A.larger than osmotic pressure
- B.smaller than osmotic pressure
- C.equal to osmotic pressure
- D.equal to atmospheric pressure
Show answer
Only a pressure greater than the osmotic pressure of seawater can push pure water backwards through the membrane. In ordinary osmosis, water moves through a semipermeable membrane from the dilute side to the concentrated side.
Read the full explanation →Which one of the following does not form oxide on reaction with oxygen?
- A.Magnesium
- B.Lead
- C.Tin
- D.Silver
Show answer
Silver sits near the bottom of the reactivity series and does not combine with oxygen even when heated in air.
Read the full explanation →The foul smell of urine of a healthy man having healthy food, when spilled on floor, is mainly due to the bacterial decomposition of
- A.urea into sulphur dioxide
- B.sugar into carbon dioxide
- C.lipids into methane
- D.urea into ammonia
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Bacteria on the floor break down the urea in urine and release ammonia, which has a sharp, pungent smell. Urea, CO(NH2)2, is the main nitrogenous waste of humans.
Read the full explanation →Which one of the following is used for storing biological tissues?
- A.Liquid nitrogen
- B.Liquid helium
- C.Liquid argon
- D.Liquid bromine
Show answer
It is very cold, chemically inert and cheap, which makes it the standard coolant for preserving cells and tissues. Liquid nitrogen boils at about −196 °C. At such low temperatures the chemical and enzyme activity inside cells almost stops, so tissues can be kept unchanged for years.
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