The simplest known cell is a bacterium with about ____ genes, but most cells contain significantly more.
A: 250
B: 350
C: 500
D: 650
A: 250
B: 350
C: 500
D: 650
举一反三
- Which of the following cells in the testis contain the most smooth endoplasmic reticulum?() A: Spermatogonium B: Leydig cell C: Smooth muscle cell D: Sertoli cell E: Spermatid
- 中碳钢也叫调质钢,常用来制造综合性能要求高的零件,淬火后常用的回火温度是( )。 A: 150~250℃ B: 250~350℃ C: 350~500℃ D: 500~650℃
- A bacterial cell transfers chromosomal genes to F- cells, but it rarely causes them to become F+. The bacterial cell is: A: Hfr. B: lysogenic. C: Auxotrophic. D: lytic.
- 中温回火的温度在( )℃范围内. A: 150~250 B: 250~500 C: 500~650 D: 650~727
- If two genes from a parent cell are on the same chromosome, which of the following best explains why the daughter cells may not have the same alleles as the parent for both genes? A: they are linked genes B: they are unlinked genes C: crossing-over D: genetic mutation