Escherichia coli is plated on nutrient agar plates that each contain a different type of antibiotic. The shaded area represents growth of the bacteria. Which of the following plates contains bacteria that were most resistant to the antibiotic?

A. 5’ TCGUTCGCU 3’: This sequence is incorrect because it contains 'U', which is a base found in RNA, not DNA. DNA contains the base 'T' for thymine, not 'U' for uracil.

B. 5’ UCGAUCGCA 3’: This option is also incorrect for the same reason as option A; it includes 'U', indicating it is an RNA sequence, not a DNA sequence.

C. 3’ AGCTAGCGT 5’: This sequence is simply the original strand read in the opposite direction, not the complementary strand.

D. 3’ TCGATCGCA 5’: This is the correct complementary DNA sequence. In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). Therefore, for the original DNA sequence 5' AGCTAGCGT 3', the complementary strand must read 3' TCGATCGCA 5', with each base pairing correctly according to the rules of base pairing in DNA. This sequence is antiparallel to the original, as indicated by the 3' and 5' ends, which is a key characteristic of DNA structure.

A. The rectum is the final section of the large intestine, terminating at the anus. It functions as a temporary storage site for feces before they are expelled from the body.

B. The jejunum is the second part of the small intestine, located between the duodenum and the ileum. It is specialized for the absorption of nutrients during digestion.

C. The cecum is a pouch connected to the junction of the small and large intestines. The vermiform appendix extends from the cecum, and although its function in humans is not entirely clear, it is believed to play a role in the immune system.

D. The ischium is not part of the digestive system; it is one of the three bones that make up the pelvis. It is important for sitting and is connected to the lower limbs.

A. A gene is a sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product, either RNA or protein. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function.

B. A locus is the specific physical location of a gene or other significant sequence on a chromosome. While a locus can contain the sequence of nucleotides that make up a gene, the term itself refers more to the position on the chromosome rather than the information for protein synthesis.

C. A promoter is a region of DNA that initiates transcription of a particular gene. Promoters are located near the transcription start sites of genes, on the same strand and upstream on the DNA. Promoters can be considered as the "on/off switch" for gene expression.

D. An operator is a segment of DNA to which a transcription factor binds to regulate gene expression by repressing it. The operator is part of an operon model which is a system that includes the operator, the promoter, and the genes that they control.

A. This option changes the population, which could introduce new variables related to gender differences in metabolism or physical performance.

B. This option introduces another variable by using two different energy drinks, which could have different ingredients and effects.

C. This option changes the distance run, which could affect the endurance aspect rather than the speed.

D. To best support the conclusion that energy drinks increase the speed of running in women, it would be most effective to conduct a controlled experiment where a variable is changed while others are kept constant. By giving half of the women water and the other half the energy drink, researchers can directly compare the effects of the energy drink against a baseline (water), which has no enhancing properties on running speed. This comparison would help to isolate the effect of the energy drink on running performance

A. Organs are more complex than tissues hence this sequence is not correct.

B. This is the most accurate sequence. Atoms are the basic units of matter and the defining structure of elements. Cells are the basic structural, functional, and biological units of all living organisms. They are the smallest units of life that can replicate independently. Tissues are groups of similar cells that work together to perform a specific function. Organs are structures made up of two or more types of tissues that work together to perform a specific function in the body. For example, the heart is an organ composed of all four types of tissue, working together to pump blood throughout the body.

C. Organs are more complex than tissues, cells and atoms hence this sequence is incorrect.

D. Atoms are less complex than cells and tissues hence they should start the sequence.

A. The cervical canal is the narrow passage through the cervix, connecting the vagina to the uterus. It is not typically the site of fertilization but rather serves as a gateway for sperm to enter the uterus and subsequently the Fallopian tubes where fertilization can occur.

B. The ovary is the female reproductive organ that produces eggs, or ova. While it is crucial for providing the egg, it is not the location where fertilization takes place.

C. The Fallopian tube, also known as the uterine tube or oviduct, is the site where fertilization usually occurs. After ovulation, the egg is captured by the fimbriae at the end of the Fallopian tube and is transported towards the uterus. If sperm are present in the Fallopian tube, fertilization can occur here.

D. The uterus is the muscular organ where the fertilized egg implants and develops into a fetus. However, it is not the typical site of fertilization; this process usually occurs in the Fallopian tubes before the zygote travels to the uterus for implantation.

A. The myocardium, is the thick, muscular middle layer of the heart's walls and is responsible for the pumping action of the heart due to its contractile cardiomyocytes.

B. The pericardium is the fibrous sac that encloses the heart providing protection and anchoring the heart within the thoracic cavity.

C. The epicardium is the outermost layer of the heart wall, also known as the visceral layer of the serous pericardium, and it provides an additional layer of protection and contains the blood vessels and nerves that supply the heart tissue.

D. The endocardium is the thin inner lining of the heart chambers and also forms the surface of the valves. It is comprised of endothelial cells and a layer of subendocardial connective tissue, which is continuous with the connective tissue of the myocardium. This layer is essential for providing a smooth lining for the chambers of the heart and the heart valves, ensuring efficient blood flow and minimizing turbulence within the heart.

A. The kidneys are a pair of bean-shaped organs located in the posterior part of the abdomen.

They are primarily responsible for filtering blood, removing waste products, and excess substances through the urine. The kidneys maintain overall fluid balance, regulate and filter minerals from blood, and create hormones that help produce red blood cells, promote bone health, and regulate blood pressure.

B. The liver, while it does process nitrogenous waste, its primary role is to detoxify chemicals and metabolize drugs. The liver secretes bile that ends up back in the intestines and also makes proteins important for blood clotting and other functions.

C. The gallbladder stores and concentrates bile produced by the liver, releasing it into the small intestine to aid in the digestion of fats. It does not remove nitrogenous waste from the body.

D. The large intestine absorbs water and salts from the material that has not been digested as food, and is passed from the small intestine. It also stores waste products until they're excreted. It is not directly involved in the removal of nitrogenous waste.

A. Parathyroid hormone (PTH) is secreted by the parathyroid glands and plays a critical role in regulating calcium levels in the blood. It acts on bones, kidneys, and the intestine to increase blood calcium levels when they are low. In the bones, PTH stimulates osteoclasts, which break down bone tissue, releasing calcium into the bloodstream. In the kidneys, it increases the reabsorption of calcium, preventing its loss through urine. Additionally, PTH influences the intestines to absorb more calcium from the food we eat.

B. Norepinephrine is a hormone and neurotransmitter involved in the body's fight or flight response. It does not regulate blood calcium levels but rather affects heart rate, blood pressure, and blood glucose levels.

C. Growth hormone, produced by the pituitary gland, stimulates growth in children and adolescents and helps to maintain muscle mass and bone density in adults. It does not directly regulate calcium levels in the blood.

D. Melatonin is a hormone secreted by the pineal gland, primarily influencing sleep-wake cycles and circadian rhythms. It does not have a role in regulating blood calcium levels.

A. The fallopian tubes are not the source of menstrual blood and tissue. They are narrow tubes that connect the ovaries to the uterus and serve as the pathway for the egg (ovum) to travel during ovulation.

B. The uterine wall, specifically the inner lining, is the source of the blood and mucosal tissue shed during menstruation. Each month, the endometrium thickens in preparation for a potential pregnancy. If fertilization does not occur, this thickened lining is shed, resulting in menstrual bleeding.

C. The vagina, is the exit route for the menstrual flow but is not the source of the blood and tissue.

D. The ovaries, which produce eggs and hormones like estrogen and progesterone, are also not the source of menstrual blood and tissue. They are involved in the menstrual cycle by triggering the thickening of the endometrium, but the tissue itself originates from the uterine wall.