1. Because carbon requires four additional electrons to fill its outermost shell
ID: 10818 • Letter: 1
Question
1. Because carbon requires four additional electrons to fill its outermost shell, it has a natural tendency to form four covalent bonds with other atoms, making it an ideal element for forming structures in living cells. (Points: 1)True
False
2. The mathematics of interpreting and organizing data is known as: (Points: 1)
algebra.
differential equations.
statistics.
graphing.
correlation and causation.
3. Sucrose is an oligosaccharide made up of which of the following sugars? (Points: 1)
glucose and glucose
deoxyribose and ribose
starch and glycogen
maltose and glucose
glucose and fructose
4. The Internet has been used as a rapid means to obtain information, including scientific ideas, but generally is less reliable tha print media because (Points: 1)
at present, the Internet is less regulated than broadcast and print media.
anyone can post "scientific" information, regardless of whether the information is misleading or not true.
individuals and/or groups maiy post information to promote their own personal interests rather than ideas that have been tested through the scientific process.
All of the above are correct.
skepticism.
5. The process by which embryonic cells go through functional and structural changes to become specialized is: (Points: 1)
metabolism.
homeostasis.
differentiation.
in vitro fertilization.
development.
6. During cell division, it is essential that the genetic material be distributed equally to the resulting cells. This is accomplished through the participation of which of the following organelles? (Points: 1)
centrioles
ribosomes
peroxisomes
Golgi apparatus
nucleolus
7. Which of the following organelles is responsible for the production of lipids? (Points: 1)
rough endoplasmic reticulum
lysosome
mitochondrion
smooth endoplasmic reticulum
centriole
8. Which of the following structures provides an internal network of support for the cell? (Points: 1)
cilia
centrioles
the cytoskeleton
nucleoli
ribosomes
9. Which of the following best explains how water moves freely across a plasma membrane? (Points: 1)
Because of the charges on phospholipids, water moves directly through the phosopholipid bilayer.
Water is brought into the cell by endocytosis and released by exocytosis.
Because water is so important to a cell, it is actively transported across the membrane.
Water moves through protein-lined channels in the plasma membrane.
The passage of water across a plasma membrane requires facilitated transport.
10. The levels of potassium and sodium in the body are regulated primarily by the hormone aldosterone. (Points: 1)
True
False
11. The process by which an embryo undergoes rapid changes in form and shape is: (Points: 1)
cleavage.
fertilization.
morphogenesis.
implantation.
differentiation.
12. Which of the following hormones stimulates the production of testosterone in males? (Points: 1)
prolactin
LH
aldosterone
FSH
growth hormone
13. Uptake of blood glucose by liver cells is stimulated by (Points: 1)
ADH
prolactin
parathyroid hormone
glucagon
insulin
14. Which of the following is true regarding estrogen and progesterone? (Points: 1)
They are secreted by the ovaries.
They are released during a female's reproductive years.
They regulate the menstrual cycle.
They stimulate the development of female secondary sex characteristics.
all of the above
Explanation / Answer
1. True. If you look at the periodic table, you can tell how many electrons an element will need to fill its outermost valence shell. Recall from simple chemistry that most molecules will "try" to achieve the electron state of their nearest noble gas. Carbon is four elemental spaces away from its nearest noble gas on the periodic table. This was set up intentionally, btw. So this is how you know that carbon will require four additional bonds (remember, a bond involves 2 electrons, 1 shared by each element) to fill its outermost valence shell. 2. I would say Statistics, but that's just what I got from process of elimination. Algebra is more linear/quadratic equations, diff eqs are calculus, causation and correlation is I don't even know what, and graphing is, well, graphing. 3. Sucrose is made from glucose and fructose. I think to think of it as, sugar comes from a plant, and the latin root word for sugar is sucr-, so plant makes me think of fructose (fruit) and glucose you just have to memorize. 4. All of the above. The internet IS less regulated and so therefore people can promote their own ideas and opinions for personal gain without regard to the consequences. 5. Differentiation. Think about it. Embryonic cells come from just one cell - the zygote. They are totipotent stem cells, meaning they can become anything (and they do, generally). So when they "grow up" and "go to college", they "pick a major" and become whatever cell they need to become. This is called differentiating. Think about it - they're becoming "different" from what they were, into a more specialized form. So instead of being cells that can become anything, they become cells with a very specific form and function. 6. Centrioles. These are the organelles which appear at the poles of a dividing cell which are responsible for sending out spindle apparatus which will each grab a chromosome at its kinetochore and make sure that the genetic information is divided equally, i.e., that each new daughter cell gets exactly the right amount of chromosomes it should have (depending on the kind of division taking place, mitosis or meiosis). 7. Smooth ER is responsible for lipid production. Rough ER deals with proteins (hence the ribosomes), lysosomes degrade unwanted cell material, mitochondrion are the organelles in which cellular respiration takes place, and I just described what centrioles are. 8. Oh come on. CytoSKELETON. You didn't really need help with this question, did you? The cytoskeleton is made up of millions of fibers ranging from microtubules to microfilaments, which are not only highways for other molecules and organelles to use to travel through the cell, but are also a support system for the cell to maintain whatever shape it's in (and yes, specialized cells have very specific shapes). 9. Hmm......well, water is a polar molecule, and the lipid bilayer is bipolar but water can't pass directly through the membrane because the hydrophobic tails of the phospholipids are on the inside of the membrane...so I would say that water comes in through protein-lined channels. 10. Yes. Aldosterone is an antidiuretic hormone which plays a major role in regulating potassium and sodium levels in the body. 11. Cleavage is a point in time in the development of an embryo when the zygote begins to rapidly divide and develop the distinctive tissues of the hypoblast, trophoblast, and epiblast. 12. LH, leutenizing hormone, is directly responsible for testosterone production. The hypothalamus of the brain signals to the pituitary to produce FSH and LH and to dump these hormones into the blood stream. They travel to the testes, where FSH will act on the Sertoli cells to release ABP (androgen-binding protein), and LH will act on the interstitial cells to release testosterone. 13. Liver cells are signaled to take up glucose by insulin. Insulin is created by the pancreas when blood glucose levels rise. The insulin acts on the liver and tells it to take up the glucose and to store it as glucagon. 14. All of the above. Estrogen and progesterone levels regulate the menstruation cycle, they are the reason why menopausal women get hormone replacement therapies (after their "reproductive years"), and they are responsible for secondary sex characteristics. They are also secreted by the ovaries and, specifically, the corpus luteum during the luteal phase of the menstrual cycle. I hope this helped!
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