Quiz About Health

Height, weight, and femur length can all be affected by environmental factors such as diet. Skin color can be affected by exposure to the sun. Blood type is entirely predictable if the parents' blood types are known.

Complementary base pairing in forming new DNA is A-T and C-G. Choices C. and D. cannot be correct, and in fact do not exist, since they mix uracil (unique to RNA) and thymine (unique to DNA).

The abyssal zone contains organisms adapted to low oxygen levels, great water pressure, and the lack of sunlight.

In a covalent bond, electrons are shared between two atoms and not totally lost or gained.

In competitive inhibition, the competition is for the active site—will it be occupied by the substrate or the inhibitor? In noncompetitive inhibition, the inhibitor occupies an allosteric site and not the active site of the enzyme.

Choices A and E can be ruled out at once, since they offer the dominant homozygous choice E or heterozygous genotype paired with a recessive phenotype—this is clearly impossible. Choice C may also be eliminated, as all offspring from a tt x tt cross would be phenotypically recessive. The phenotypic ratio for the F1 is 735:265 for normal:twisted ears, or about 3:1. A 3:1 phenotypic ratio is associated with a 1:2:1 genotypic ratio, and both ratios will result from a crossing of heterozygotes parents, in this case, Tt x Tt. A Punnett square solution will verify this conclusion.

The importance of the three-dimensional shape of proteins cannot be overstated: it is the basis of assembling a functional protein, such as an enzyme or antibody. The orientation of different portions of the protein molecule is shaped by interactions with the aqueous (water) environment and associations between amino acids in different places in the molecule. Ultimately, and most profoundly, all of this is dependent upon the primary structure, since the primary structure (order of amino acids) of a protein is all that is coded for in an organisms DNA.

A climax community is in a state of dynamic equilibrium with its environment, meaning that it does change, but on average it will be almost the same. A climax forest will be predominantly hardwoods, but some softwoods (pines) will remain.

Karyotyping involves taking photographs of chromosomes during metaphase in mitosis; normal and abnormal chromosomes can then be identified by appearance and numbers. Down syndrome in humans can be readily diagnosed, since it is a result of having a third chromosome number 21 accompanying the normal pair of chromosomes. This is termed a trisomy, specifically trisomy 21, referring to the three chromosomes. Other examples of trisomy are Patau syndrome (trisomy 13) and Edward's syndrome (trisomy 18). While a genetic factor is hypothesized as a factor in alcoholism, it is not proven, and in any case it does not change the karyotype. Hemophilia, Huntington's chorea, and phenylketonuria are known inherited disorders, but again, they do not affect the karyotype.

Mitosis is directed toward producing daughter cells that are identical to the parent cell. As much as possible, variation is eliminated or reduced. Fertilization usually combines chromosomes (and their genes) from two lineages. Meiosis produces gametes that are not identical; crossing over is usually part of this process. Mutation can make fundamental changes in the genetic code.

Examples are crayfish and lobsters. Arachnida are the spiders, and Merostomata is the class to which horseshoe crabs belong. Arthropoda is a phylum, not a class.

The colors of the axons form the basis for classifying regions of the CNS as made up of white or gray matter. In the brain, the gray matter is on the outside, and the white matter on the inside. In the spinal cord, the situation is reversed, with the gray matter on the inside, and white matter on the inside. Myelin is a fatty insulating material.

The sentence describes coral reefs. The classification coral reef zone is also sometimes used. The neritic zone lies over the continental shelves. It is sunlit, and photosynthesis occurs. Oxygen levels are high. The euphotic zone is made up of ocean waters down to the limit of sunlight penetration. Photosynthesis occurs here as well, resulting in high oxygen levels. The bathyal zone is deeper and darker than the euphotic zone and unable to support photosynthesis. Oxygen levels are therefore low. The deepest zone is the abyssal, where no light penetrates. It has low oxygen levels and is cold.

A watershed is the area of land that receives rainfall and channels it into a stream. Point source pollution comes from single, readily identified places, such as factories or golf courses. "Wide" would not be used with "point source pollution".

A liverwort is a type of bryophyte (a non-vascular plant), and not a vascular fern (Pterophyta). A gingko is a type of gymnosperm, although gymnosperm is used today more often informally rather than in any strict taxonomic sense.

An example is poisoning the process of ATP production or hydrolysis in a cell. This stops the sodium-potassium pump from moving Na+ and K+ ions across the cell membrane. This active transport pump is dependent on ATP for energy.

Yeasts, although once classified as plants, are now classified as members of the kingdom Fungi.

While niche is sometimes used loosely to describe the part of the habitat occupied by a species, this is not the correct biological use of the word. This rules out choices B. and E., while choice C. is clearly wrong. Choice D. would be correct if the phrasing were changed from occupied by many related species to occupied by one species. Niches do overlap sometimes, but usually organisms occupy different niches, minimizing competition. If two species do occupy the same niche, competition will soon get rid of one of them—this is known as competitive exclusion.

Sealum is a phonetic spelling of coelom. Archenteron is the cavity found within an embryo at the gastrula stage.

First the sperm fertilizes the egg, and the zygote repeatedly divides in many cells (cleavage) without an increase in size. Three basic cell layers (ecto-, meso-, and endoderm) are formed next during gastrulation, followed by notochord and dorsal nerve cord development (neurulation). The formation of the neural crest is next, proceeding to organogenesis, the stage in which the organs are formed.

Sponges are classified as the phylum Porifera. Jellyfish (Cnidaria) have true tissues and are radially symmetrical.

The Cambrian and Ordovician periods (not eras) are subdivisions of the Paleozoic Era.

Uracil (U) is found in RNA instead of thymine (T). The other difference between RNA and DNA is that the 5-carbon sugar in DNA is deoxyribose, while in RNA it is ribose.

Choices A. and C. are producers. They harness the energy of sunlight in photosynthesis and channel the energy into the ecosystem through the food chain. Choices B. and D. are consumers—herbivores and carnivores, respectively. Wastes are called detritus. Fungi and bacteria (insects are another member of this group) as detritivores (decomposers) break down the wastes and dead bodies of other organisms

The sympathetic nervous system and parasympathetic nervous system usually act in opposition to each other. The sympathetic nervous system causes dilation of the bronchioles, while the parasympathetic causes constriction. The sympathetic decreases the secretions of the stomach and reduces intestinal motility, while speeding up the heartbeat; the parasympathetic increases both secretions and motility but slows the heartbeat. Smooth and cardiac muscles, and most glands, are controlled by the contrasting and opposite information from these two parts of the autonomic nervous system.

Releasers are stimuli that evoke a response of stereotypical behavior. Both the stimulus and the response are very specific.

The sympathetic nervous system is usually identified with the flight or fight response. The other choices are incorrect or too general. For instance, the sympathetic and parasympathetic nervous systems together make up the autonomic nervous system. The central nervous system consists of the brain and spinal cord. The somatic nervous system is made up of sensory and motor nerves and controls skeletal (voluntary, striated) muscles.

The cone size matches the size of the spores it produces. The larger female cones produce megaspores, while the smaller male cones produce microspores. Gymnosperms such as conifers and other higher plants do not have motile sperm, a characteristic associated with plants such as bryophytes, which require water or wet conditions for sperm to move.

Echinoderms, characterized by radial symmetry and tube feet, are represented today by only four classes. Many other echinoderm classes are extinct. This lineage has not led to significant, further evolutionary innovations, while the chordate line has (e.g., vertebrates).

Decomposers (detritivores) such as fungi, bacteria, insects, and soil organisms break down the wastes and remains of organisms that litter the ecosystem, and they release tied-up nutrients into the environment, where they are recycled by plants. Sunlight is the source of energy at the base of the herbivore food chain.

Choices B. and D. may be cast aside at once, since they state genotypic ratios rather than the phenotypic ratios required by the question. The genotype of the wrinkled parent flies is known to be ss, but the genotype of the straight-wing variety can be SS or Ss. Therefore, two crosses are possible with the parents: (1) SS x ss and (2) Ss x ss. As a Punnett square will show, only the cross of SS x ss will yield F1 progeny that all have straight wings. The genotype of such progeny is Ss. Crossing these to obtain the F₂ generation will give a genotype of 1:2:1 for SS:Ss:ss, and a phenotype of 3:1 for straight:wrinkled.

Breeding activities in most birds are cued by the increasingly long days that occur in spring.

Three fluid-filled, semicircular canals are arranged within the inner ear to detect motion in any direction. Hair cells are stimulated by fluid movement resulting from motion. Otoliths are gravity-sensor cells used for determining balance. The other three terms refer to auditory parts of the ear.

Outside the cell, the water is in a higher concentration than inside the cell, and in osmosis water always moves from an area of higher water concentration to an area of lower water concentration.

The thallus is an undifferentiated plant body that may form simple or branched filaments, and may be multi-cellular or single-celled.

Pectoral fins and wings meet the tests of homology: they can be shown to have a common genetic and developmental origin. Each is a modification of the same basic anatomical structure, the vertebrate limb. The wings of bees and birds, by contrast, are functionally similar, but no more than that. Their evolutionary origins are individually unique, and there is no developmental commonality. In no sense do they share a common developmental or evolutionary origin. Human and octopus eyes are indeed anatomically similar, but like the other incorrect examples, they are distinct and separate innovations in evolution.

The microspores develop into pollen grains, each possessing a pollen tube and sperm nucleus. The stigma and pistils are female, not male, flower parts.

Part of the definition of alleles is that they are alternative forms of a gene. Alleles therefore must be found at that gene's locus. Choice A. is incorrect; multiple alleles are common in populations. Choice C. is incorrect and misleading; it is true only of diploid cells. Haploid cells (gametes, haploid somatic cells from organisms such as mosses), of course, cannot possess more than one allele of a gene. Choice D. is incorrect, since even a diploid individual is restricted to possessing two different alleles of a gene. Choice E. is completely false.

The first jawless fishes arose during the Cambrian; they have descendants in modern lampreys and hagfish. Tunicates are chordates but not vertebrates.

A phenotype of 3:1, normal:twisted, always results from an underlying genotype of 1:2:1 for TT:Tt:tt.

Atmospheric nitrogen is converted to ammonia (NH₃) by bacteria, then to nitrite (NO₂- ion), and finally nitrate (NO₃- ion). Atmospheric carbon dioxide is fixed by green plants and algae during photosynthesis.

During aerobic work (free oxygen is readily available), cells can derive energy from glucose and fatty acids and work for a long time, until glycogen stores are exhausted. In anaerobic exercise (free oxygen is not available in sufficient supply), the ability to work is much more limited, and fatigue sets in rapidly. Fermentation must be used as a source of ATP, producing lactic acid that builds up (lowering the pH), causing pain in the muscle. Since the ATP derived from glycogen is much less in anaerobic than aerobic work, glycogen is more quickly used up in anaerobic than aerobic activities. The combination of chemical changes and glycogen depletion soon causes the muscle to fatigue.

The left ventricle is the main pumping chamber of the heart and services the entire systemic circulation. The thinner-walled right ventricle pumps blood only to the lungs. The atria are weaker and have thinner muscular walls than either ventricle.

Sarcolemma is a plasma membrane surrounding groups of the myofibrils that make up striated (skeletal) muscle fibers. Without specific knowledge of the answer, choices A. and E. are likely candidates, as both contain sarco-, which is specific for terms relating to muscles. Sarcoplasmic reticulum is the endoplasmic reticulum of muscles. The sacculus is not involved with muscles but is part of the vertebrate inner ear.

Bryophytes and ferns have motile sperm, which are dependent upon a film of water for mobility to fertilize the eggs.

Kidneys and nephrons are vertebrate structures. A Malpighian corpuscle is a unit of the nephron consisting of the glomerulus and Bowmans capsule. Malpighian tubules remove wastes from the hemocoel to the intestine.

The genetic code is redundant and degenerate. If each mRNA codon consisted of one of the four RNA nucleotides, only four of the 20 amino acids could be coded for. If two nucleotides were used per codon, only 16 amino acids could be coded for, still falling four short. With three nucleotides per codon, 64 distinct codons exist, resulting in a surplus of codons. Of the 64 codons, 61 code for amino acids, one (AUG) codes for both start and the amino acid methionine, and three code for stop.

Epidermal cells in the root absorb water, usually through projections from the cell (root hairs). These root hairs are parts of a cell, cytoplasmic extensions, and not small roots themselves. Xylem transports water within the plant but does not absorb water into the plant.

The x-axis is increasing temperature, and the y-axis shows the rate of photosynthesis measured as carbon dioxide uptake. Higher rates of photosynthesis will consume more carbon dioxide. In this study, the rate of carbon dioxide uptake by plants over a range of temperatures was measured as a way of determining how the rate of photosynthesis is affected by temperature. C₄ plants are known to be better adapted for carrying out photosynthesis at elevated environmental temperature than are C₃ plants. This is shown by the graph. C₄ (LINE ONE) plants continue to function well at higher temperatures, while C₃ (LINE TWO) plants show a decrease in photosynthesis carried out as temperatures become more extreme. Note that at the higher temperatures, the C₄ plants have a higher rate of photosynthesis compared with C₃ plants. The actual rate of C₄ carbon dioxide uptake is basically unchanged as the temperature increases, while the line for the C₃ plants falls off. At lower temperatures, the C₃ plants are more efficient than the C₄ plants.

Pancreatic juice (a digestive juice) is secreted by acinar cells (acini), as is suggested by their alternate name of exocrine cells. Hormones are endocrine, not exocrine, secretions. The bulk of the gland is made up of such cells. Within that tissue exists another tissue in islands or islets, called the islets of Langerhans, which secrete insulin (from beta cells) and glucagon (from alpha cells).