Which of the following is not characteristic of mycoplasmas?
a. Cytochromes
b. Sterols in cytoplasmic membranes
c. Use of UGA codon for tryptophan
d. rRNA nucleotide sequences similar to those of Gram-positive bacteria

검증된 단계별 안내

Step 1: Understand the general characteristics of mycoplasmas. Mycoplasmas are a group of bacteria that lack a cell wall and have unique features compared to other bacteria.

Step 2: Review the options given: (a) Cytochromes, (b) Sterols in cytoplasmic membranes, (c) Use of UGA codon for tryptophan, and (d) rRNA nucleotide sequences similar to those of Gram-positive bacteria.

Step 3: Recall that mycoplasmas contain sterols in their cytoplasmic membranes, which is unusual for bacteria, and they use the UGA codon to code for tryptophan instead of a stop signal.

Step 4: Remember that mycoplasmas have rRNA sequences closely related to Gram-positive bacteria, supporting their classification within this group.

Step 5: Identify that cytochromes are typically involved in electron transport chains and are not characteristic of mycoplasmas, which have limited metabolic capabilities and often lack cytochromes.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

영상 길이:

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Mycoplasma Cell Membrane Composition

Mycoplasmas are unique among bacteria because they lack a cell wall and incorporate sterols into their cytoplasmic membranes to provide structural stability. This feature distinguishes them from most other bacteria, which do not have sterols in their membranes.

Genetic Code Variations in Mycoplasmas

Mycoplasmas use a slightly altered genetic code where the UGA codon, normally a stop signal in most organisms, codes for the amino acid tryptophan. This deviation is a key molecular characteristic important for identifying and understanding mycoplasma genetics.

Phylogenetic Relationship Based on rRNA Sequences

The rRNA nucleotide sequences of mycoplasmas show close similarity to those of Gram-positive bacteria, indicating their evolutionary relationship. This molecular evidence helps classify mycoplasmas within the bacterial domain despite their unique features.

Which of the following is not characteristic of mycoplasmas?a. Cytochromesb. Sterols in cytoplasmic membranesc. Use of UGA codon for tryptophand. rRNA nucleotide sequences similar to those of Gram-positive bacteria