Describe the pressure-flow hypothesis
What will be an ideal response?
The pressure-flow hypothesis describes the flow of sugar and water in phloem. Photosynthetic cells in the leaves produce sugar, and the companion cells actively transport the sugars into the phloem's seive tube elements. Water follows passively by osmosis from the adjacent xylem. This increases the water pressure in the phloem, and the solution moves downward in the plant. At the sink (the nonphotosynthetic cells), sugar is again actively transported out of the phloem, and water follows by osmosis back into the xylem, where it is then moved upwards again.
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If a female parent is a carrier, due to the presence on the X chromosome of one copy of the recessive allele responsible for the trait being studied, what are the odds that a male child would be affected?
a. 0 b. 25% c. 50% d. 75% e. 100%
Leaves and flowers exhibit indeterminate growth
____________________Leaves and flowers exhibit indeterminate growth. ____________________
The _____ oncogene, the ____ in human cancer, causes cells to become cancerous due to abnormal cell signaling
a. BRCA1; most common b. Ras; most common c. BRCA1; least common d. Ras; least common e. BRCA2; most common
Considering only the steps that take place during translation, which of the following is not needed in order for translation to occur?
A) DNA template B) ribosomes C) tRNA D) sources of energy, including ATP