Describe the structure and organization of the rDNA repeat unit in eukaryotes
What will be an ideal response?
The rDNA repeat unit exists in tandem arrays of 100s to 1,000s of copies. Each unit consists of coding sequences for three rRNA genes (18S, 5.8S, and 28S) separated by two internal transcribed spacer (ITS) regions. The genes are flanked by external transcribed spacer (ETS) regions. These regions comprise the ribosomal DNA transcription unit. Upstream of the unit and separating from the previous repeat unit is a nontranscribed spacer (NTS) region that contains the promoter.
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Areas of the chromosome that remain highly condensed are called ______
A. Euchromatin B. Facultative heterochromatin C. Constitutive heterochromatin D. Barr body
The donor cell makes ___________ whose function is to bring F- cells close enough to transfer a ___________ to the recipient.
A. a sex pilus, single strand of DNA B. a sex pilus, double strand of DNA C. an F factor, fertility plasmid D. an F factor, replicated F factor E. a sex pilus, bacterial chromosome
Menstrual flow results in the discharge of ____
a. the follicle b. the corpus luteum c. the lining of the endometrium d. surface cells from the vagina e. blood from vessels on the outer side of the uterus
Which of the following is not a fat-soluble vitamin? Fat-soluble vitamins may be harmful if taken in large doses, as they accumulate in our fatty tissues
a. A b. B c. D d. E e. K