<span>The 8 month old infant is at risk for an allergic reaction. You should never give a child under the age of one any honey. The nurse should inform the parent that giving honey to a child under the age of one is dangerous and can cause an allergic reaction.</span>
Answer: C) a factor that may affect an experiment or investigation
Explanation:
This is the best answer. A and B can be eliminated. D describes a controlled variable which is more specific than a scientific variable, thus C is the best answer. It is the best description of just a scientific variable.
Answer:
<u>d. Transport proteins within the membrane serve as a tunnel for molecules to enter the cell.
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Explanation:
Solutes are typically moved across the cell through either passive or active transport. The cells, surrounded by a bilipid layer or plasma membrane is amphiphlic- its polar, hydrophilic lipid heads face outwards, while their non-polar hydrophobic lipid tails face inwards towards each other.
While lipid-soluble molecules move across the layer easily, it is also difficult for charged and also large molecules to move across its surface, into the cell. Transmembrane channels, <u>embedded within the membrane</u>, help to maintain selective permeability as transport proteins, pores and gated channels. Simple diffusion happens as a method of passive transport in cells through plasma membranes.
The solutes travel through the plasma membrane in the process of diffusion from regions of high concentration to regions of low concentration; this occurs without the use of energy. <u>Molecules moving against their concentration require active transport mechanism to cross the membrane</u>.
Answer:
Estrogen and progesterone are both involved in preparing the endometrium for embryo implantation. Estrogen helps to ensure conception by increasing the amount of secretory glands in the uterus. Estrogen also increases blood supply to the endometrium.
Progesterone is crucial for embryo implantation and maintenance of pregnancy. Progesterone also enlarges secretory glands that produce carbohydrates, proteins and mucin that are required for embryo nourishment before implantation. Progesterone stabilizes endometrial muscles to prevent them from contracting during pregnancy.
Explanation:
- Estrogen and progesterone are steroid hormones of the reproductive system. Estrogen helps in conception whereas progesterone maintains pregnancy.
- Estrogen is secreted during the follicular phase of the menstrual cycle that promotes the growth and maturation of follicles in the ovary.
- Estrogen also induces oestrous behavior in females.
- Secreted by the corpus luteum, progesterone is also a steroid hormone, responsible for implantation of the embryo in the uterus.
