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Question
The "spiral staircase" structure of DNA is referred to as the
A. tertiary structure.
B. spiral structure.
C. the double helix.
D. the twist of life.
Answer
This answer is hidden. It contains 1 characters.
Related questions
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The Leydig cells of the testes constitute a blood-testis barrier that prevents autoimmune destruction of the sperm.
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C. high concentrations of testosterone.
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Women do not enter a refractory period following orgasm and are capable of multiple orgasms.
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Which of the following is a precursor to melatonin synthesis?
A. tryptophan
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The role of melatonin in puberty of humans is well established and critical.
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Pubic and axillary hair growth at puberty is from increased secretion of
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Epiphyseal growth in males is stimulated by estrogen.
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A male with 5 alpha-reductase deficiency will have male internal sex organs but more female appearing external genitals.
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Treating a male fetus with antibodies to DHT would prevent development of the epididymides.
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Female accessory sex organs develop from the mesonephric ducts.
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How many chromosomes are found in a normal human cell?
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B. 23 pair
C. 46
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Cryptorchid males do not produce testosterone.
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A. IgA
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C. IgF
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What hormone is secreted by the anterior pituitary that stimulates production of milk proteins?
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Genetic screening of newborns using only a drop of blood can determine which of the following genetic disorders?
A. hypothyroidism
B. cystic fibrosis
C. sickle cell anemia
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What hormone may play a role in reducing the size of the uterus following delivery?
A. progesterone
B. prostaglandin
C. oxytocin
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DHEAS travels from the fetal adrenal cortex to the placenta where it is converted into oxytocin.
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Cortisol from the fetal adrenal gland will stimulate maturation of the lungs and production of surfactant.
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Blood within the umbilical ___________ contain(s) high concentrations of fetal waste products.
arteries
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A. zygote.
B. morula.
C. blastocyst.
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The progressive fusion of the acrosomal membrane with the plasma membrane of the sperm is called the
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B. acrosomal reaction.
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After meiosis I in males, ________ are formed.
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B. secondary spermatocytes
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Hypocalcemia enhances the excitability of nerves and muscles because of the ____ permeability of the cell membrane to ___.
A. increased, K+
B. decreased, K+
C. increased, Na+
D. decreased, Na+
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Cells synthesizing hydroxyapatite in bones are termed as
A. osteoblasts.
B. osteoclasts.
C. osteocytes.
D. osteosarcoma cells.
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Bone resorption is produced by the action of _____________, which return bone calcium and phosphate to the blood.
A. osteoblasts
B. osteoclasts
C. osteocytes
D. calcitonin