The head of a phospholipid is hydrophilic, and the tails are hydrophobic. The phosphate head is charged and therefore polar. All other answers are correct.

Notice the question states NOT. All the other answer choices are correct. Water moves up the plant through the xylem by passive transport because of the physical properties of water. Choice D refers to the use of a heat sink, which is necessary in this experiment to make sure that the temperature does not rise during the experiment. If the temperature did rise, it would constitute another variable in the experiment.

Vaccinations are given to immunize against a particular antigen. They increase the number of a particular white blood cell that recognizes and binds to a particular antigen.

G-protein coupled receptors are located on the extracellular membrane. This means that cortisol, a hydrophobic hormone that passes through the cell membrane, is not involved. Once activated the order in which the mechanism of action occurring is GPCR → G-Protein → Adenelyl Cyclase → cAMP

If 40% of the DNA sequence is made of thymine that means its base pair, Adenine also comprises 40% of the DNA sequence. 20% of the DNA sequence is therefore split equally between the two remaining base pairs, Guanine and Cytosine. Therefore, 10% of the DNA sequence is comprised of Guanine.

Hydrogen bonding determines secondary and tertiary structure but not primary.

Pioneer organisms colonize an area that is not habitable by other organisms and alter it over time in a way that makes the area habitable for other organisms. Pioneer organisms are producers, such as lichens that are symbionts—an intertwined relationship of a fungus and an algae.

The oxygen released by plants is produced during the light reactions of photosynthesis. The main inputs to the light reactions are water and light. Water is the source of the oxygen.

The Calvin cycle is the light-independent reaction that occurs during photosynthesis. Familiarise yourself with the different steps of the cycle.

Innate immunity and adaptive immunity do not refer to the same thing. Innate immunity is the inborn, nonspecific first and second lines of defense. Adaptive immunity is specific and involves antigens and antibodies. Adapative immunity follows innate immunity and is slower. Adaptive immunity involves the humoral (antibody) response. Dendritic cells are antigen-presenting cells.

Notice the question says NOT. A lymphocyte has receptors for only one type of antigen. The other statements are correct.

Endotherms are organisms whose metabolic rates do not respond to shifts in environmental temperature.

The definition of Hardy-Weinberg equilibrium is that the allelic frequencies will not change. If one trait becomes advantageous and the allelic frequency changes, then the population is no longer in Hardy-Weinberg equilibrium.

Glycolysis would cease if there were not a constant supply of NAD⁺ to bind to hydrogen. Glycolysis produces pyruvate, which is the raw material for the citric acid cycle, not oxidative phosphorylation. Glyocolysis does occur in the cytoplasm, but that is not important.

The father's genotype is X-Y; the mother's is XX. In this case, the father passes his X-gene to all their daughters. So all the daughters inherit the X-gene and are carriers of hemophilia. He passes his Y chromosome to his sons which means none of his sons will have hemophilia.

In an autoimmune disease, the immune system mistakenly attacks its own body structures. The antibodies attack the postsynaptic muscle receptors, not the neuron function.

Facultative anaerobes can grow in both the presence or absence of oxygen. The cell will begin to divide rapidly because larger cells require more oxygen and glucose than smaller ones

This cladogram does not have a time scale attached to it. All we can say about any clade or lineage is that one evolved earlier or later than another. A cladogram is constructed to show the development of different traits and the lineage of related organisms that evolved with that trait.

Some scientists believe that some complex molecules necessary for life on Earth might have come from outer space. That might be true. However, the purpose of Miller's experiment was to demonstrate that the molecules necessary for life to develop could have formed under the conditions of the early Earth. He did not succeed in demonstrating that the first molecules were self-replicating.

Prokaryotes do not have internal membranes. They do not have a defined nucleus. Instead, they have DNA in a nucleoid region. All cells carry out cellular respiration, but they do not necessarily do it in mitochondria. The surface-to-volume ratio of cells varies with the cell's size. Smaller cells have a greater surface-to-volume ratio.

Apoptosis is anything but random. It is controlled by both internal and external signals that lead a class of enzymes called caspases to assist in the digesting of a cell marked for apoptosis.

Cell walls are present in prokaryotes but not eukaryotic animal cells. Ribosomes and cell membranes are present in both of them. Chloroplasts and large central vacuoles are not seen in either of them. Animal cells have small vacuoles. Chitin may or may not be found in prokaryotes and can therefore not be used to distinguish the two.

Polygenic traits are traits that require the input of multiple genes to determine the phenotype. Skin color is a classic example of a polygenic trait; three genes combine to provide the various shades of skin tone seen in humans.

RNA processing occurs before the preRNA transcript leaves the nucleus. Introns, which are intervening sequences, are removed. Exons are the expressed sequences, which are the genes or coding regions.

A frameshift mutation is one in which the reading frame for the protein construction machinery is shifted. It is a deletion or addition of nucleotides in a number that is not a multiple of 3. Often this can lead to premature stop codons, which lead to nonfunctional proteins.

This is the definition of the primary structure. Secondary Structure (B) refers to the initial folding of a polypeptide into shapes and is stabilized by hydrogen bonds between backbone NH and CO groups. (E) is an example of a secondary structure. Tertiary Structure (C) refers to the interactions between amino acid residues located distantly from each other on a polypeptide chain. Quaternary Structure (D) refers to the interactions between different polypeptide subunits

Humans and chimps share an ancestor that walked upright about 6–7 million years ago.

Although it is true that during the Krebs cycle pyruvate is completely broken down to CO₂, the most energy from cellular respiration is released during oxidative phosphorylation, when all the energy stored in NADH and FADH₂ from previous stages of cellular respiration is released.

The question does not give you enough background to determine anything more than to say that some traits are favored more than others in a particular environment.

This is an accurate description of an autoimmune disease.

The acrosome reaction enables the sperm to penetrate the coat surrounding the ovum. The cortical reaction ensures that a fertilization membrane forms and prevents another sperm from penetrating the egg. The cortical reaction is responsible for a slow block to polyspermy.

The point of meiosis is variation. Daughter cells are different from the parent cells as well as each other. Homologues pair during prophase I, not prophase II. DNA replication occurs before meiosis I only.

Memory B cells are able to recognize foreign invaders if they come back into our systems and lead to a more rapid and efficient attack on the invader.

Glycolysis is the first portion of cellular respiration. Familiarise yourself with the different reactants and products listed below.

The coupling of exergonic and endergonic reactions is an important biochemical strategy. The exergonic flow of electrons in the cristae membrane of mitochondria provides the energy to pump protons across the cristae membrane and maintain a gradient.

A mutation in AUG would have disastrous consequences because translation could not begin. Choice C refers to what happens after transcription. RNA processing occurs after transcription.