IB Biology Practice Test Quiz

The statement "Cells come from pre-existing cells" is part of the cell theory. This theory states that all living organisms are composed of cells, cells are the basic unit of structure and function in living organisms, and cells can only arise from pre-existing cells through cell division. This statement supports the idea that new cells are formed through the division of existing cells, rather than spontaneously appearing.

Proteins are synthesized on ribosomes attached to the rough endoplasmic reticulum (ER). After synthesis, the proteins are transported from the rough ER to the Golgi apparatus for further processing and modification. The Golgi apparatus then packages the proteins into vesicles and transports them to the plasma membrane for export out of the cell. Therefore, the correct route for exporting proteins from the cell is rough endoplasmic reticulum → Golgi apparatus → plasma membrane.

Both prokaryotes and eukaryotes have ribosomes, but they differ in size. Prokaryotes have 70S ribosomes, while eukaryotes have 80S ribosomes. Additionally, both types of cells have DNA, but it is organized differently. Prokaryotes have naked DNA, meaning it is not associated with proteins, while eukaryotes have DNA that is associated with proteins. Therefore, the correct answer is prokaryote-eukaryote-prokaryote-eukaryote.

The standard deviation measures the amount of variation or dispersion in a set of data. In this case, we know that 68% of the lengths fell within a range between 15 mm and 45 mm, and the mean is 30 mm. This means that the data is fairly spread out around the mean. Since the range is 30 mm (45 mm - 15 mm), and the data is evenly distributed within this range, we can assume that the standard deviation is half of the range, which is 15 mm. Therefore, the standard deviation of this sample is 15 mm.

The diagram represents a biochemical pathway in a yeast cell. Compound II in the diagram is correctly identified as pyruvate. This is because pyruvate is a key intermediate molecule in the process of glycolysis, which is shown in the diagram. Pyruvate is produced from glucose and serves as a precursor for various metabolic pathways, including fermentation or conversion to acetyl-CoA for entry into the citric acid cycle. Therefore, based on the pathway and the role of compound II, it can be concluded that II is pyruvate.

Proteins in prokaryotes contain sulfur. Sulfur is an essential element in the structure of certain amino acids, such as cysteine and methionine, which are building blocks of proteins. These sulfur-containing amino acids play important roles in protein folding, enzyme activity, and protein-protein interactions. Therefore, proteins are the substance in prokaryotes that contain sulfur.

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If (N + M) = (I + E) = 0, it means that the number of individuals being born (natality) and dying (mortality) is equal to the number of individuals immigrating and emigrating. This indicates that the population is not experiencing any net growth or decline. In the plateau phase, the population size remains relatively stable over time. Therefore, the correct answer is Plateau phase.

The rate of oxygen production in photosynthesis is influenced by temperature and the wavelength of light. Temperature affects the activity of enzymes involved in the photosynthetic process, and different wavelengths of light are absorbed by different pigments in the chloroplasts, which affects the rate of photosynthesis. The number of mitochondria, on the other hand, is not directly related to the rate of oxygen production in photosynthesis.

A community refers to a group of populations of different species that live in the same area and interact with each other. This interaction can involve various types of relationships such as competition, predation, and mutualism. The populations within a community are interconnected and depend on each other for resources and survival.

The correct answer is glucose fatty acid. This is because glucose is a type of sugar molecule and fatty acid is a type of lipid molecule. These two molecules have different structures and functions in the body. Amino acids are the building blocks of proteins, so the combinations of ribose or glucose with amino acids would not be accurate descriptions.

A base substitution in the hemoglobin gene is the cause of the amino acid valine replacing glutamic acid in some people's hemoglobin. This means that during the replication of the DNA, there was a change in one of the bases, resulting in a different amino acid being coded for. This change in the genetic code leads to the incorporation of valine instead of glutamic acid in the hemoglobin protein.

Homologous structures and selective breeding of domesticated animals are both used as evidence for evolution. Homologous structures are similar structures found in different species that suggest a common ancestor. This similarity indicates that these species have evolved from a common ancestor and have adapted to different environments over time. Selective breeding of domesticated animals also provides evidence for evolution as it demonstrates how humans have artificially selected certain traits and bred animals with those traits, leading to the development of new breeds. The overproduction of offspring, on the other hand, is not directly used as evidence for evolution but is a consequence of natural selection.

Okazaki fragments are short, discontinuous DNA fragments that are formed on the lagging strand during DNA replication. This is because DNA replication occurs in a 5′ → 3′ direction, and the lagging strand is synthesized in the opposite direction. Therefore, the lagging strand is synthesized in short fragments, with each Okazaki fragment serving as a template for the synthesis of a new DNA strand. This allows for the efficient replication of the lagging strand and ensures that both strands of the DNA molecule are accurately replicated.

The characteristics described in the question, such as radial symmetry, a sac-like body with only one opening, and tentacles with stinging structures, are all typical of animals belonging to the phylum Cnidaria. Cnidarians include jellyfish, sea anemones, and corals, which exhibit these specific traits.

A pyramid of energy represents the flow of energy through different trophic levels in an ecosystem. It shows the amount of energy transferred from one trophic level to the next. The units of a pyramid of energy are typically represented in kilocalories (kcal) or joules (J) per unit area per unit time, such as kcal/m²/year or J/m²/year. This unit indicates the amount of energy that is available to the organisms at each trophic level and demonstrates the decrease in energy as it moves up the food chain.

Antibiotics work by targeting the metabolic processes of bacteria, which are different from those of viruses. Viruses do not have their own metabolism and rely on host cells to replicate. Therefore, antibiotics, which are designed to inhibit bacterial metabolic pathways, are not effective against viruses.

This pedigree chart shows X-linked recessive inheritance. This means that the trait being observed is located on the X chromosome, and it is recessive, meaning that individuals need to inherit two copies of the trait to express it. Since the trait is recessive, it is more commonly observed in males who only have one X chromosome. Females, on the other hand, need to inherit the trait from both parents to express it. This pattern of inheritance is consistent with X-linked recessive inheritance.

The labels X, Y, and Z indicate the following structures: right atrium, pulmonary artery, and semi-lunar valve, respectively.

At stage 1, Na+ ions diffuse into the cell, causing the inside of the cell to become more positive. This is known as depolarization. At stage 2, K+ ions diffuse out of the cell, causing the inside of the cell to become more negative. This is known as repolarization.

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In a test cross, a suspected heterozygous individual is crossed with a homozygous recessive individual. This is done to determine the genotype of the suspected heterozygote. If the offspring show the dominant phenotype, it means that the suspected individual is heterozygous. However, if the offspring show the recessive phenotype, it indicates that the suspected individual is homozygous dominant. By crossing with a homozygous recessive individual, the recessive allele can be revealed if it is present in the suspected heterozygote.

During the formation of mature RNA in eukaryotes, introns are removed. Introns are non-coding sequences of DNA that are transcribed into RNA but are not involved in the synthesis of proteins. They are removed through a process called RNA splicing, where the introns are cut out and the remaining exons are joined together to form the mature RNA molecule. This process ensures that only the necessary coding sequences are present in the final RNA product, allowing for the synthesis of functional proteins.

Testosterone plays a crucial role in the pre-natal development of male genitalia, such as the penis and testes. It is responsible for the differentiation and maturation of these reproductive organs. Additionally, testosterone is involved in the development of secondary sexual characteristics in males, including the deepening of the voice, growth of facial and body hair, and increased muscle mass. These characteristics typically emerge during puberty, when testosterone levels increase significantly.

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During interphase, which is the longest phase of the cell cycle, DNA replication occurs. This is the process in which the DNA molecule is duplicated to prepare for cell division. The re-formation of nuclear membranes occurs during the telophase stage of mitosis, which is the final stage of cell division. Therefore, the correct answer is I and III only.

The external intercostal muscles and diaphragm contract to cause air to pass into the lungs through the trachea. The external intercostal muscles are located between the ribs and play a role in elevating the ribcage during inhalation, while the diaphragm is a dome-shaped muscle located at the base of the lungs that contracts and flattens during inhalation, increasing the volume of the thoracic cavity and allowing air to enter the lungs. Together, these muscles work to expand the chest cavity and create a pressure gradient that draws air into the lungs.

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HCG, or human chorionic gonadotropin, plays a crucial role in early pregnancy by preventing the degeneration of the corpus luteum. The corpus luteum is a temporary structure that forms in the ovary after ovulation and produces progesterone, which is essential for maintaining the uterine lining and supporting a pregnancy. HCG acts as a signal to the corpus luteum to continue producing progesterone, ensuring the survival of the pregnancy. Without HCG, the corpus luteum would degenerate, leading to a decrease in progesterone levels and the potential loss of the pregnancy.

In the given diagram, the structure indicated by the letter Y is Bowman's capsule. This is supported by the fact that Bowman's capsule is listed as an option directly below the letter Y. Similarly, the structure indicated by the letter Z is the distal convoluted tubule, as it is the only option listed directly below the letter Z.

Lipase is an enzyme that breaks down lipids, specifically triglycerides, into fatty acids and glycerol. It is primarily produced in the pancreas and is active in the small intestine. The pH optimum for lipase activity is 8, which means it functions most efficiently at a slightly alkaline pH. Therefore, the correct answer is "triglycerides, pancreas, pH = 8."

Non-competitive inhibition occurs when the inhibitor molecule binds to a site on the enzyme other than the active site. This means that the inhibitor does not resemble the substrate, as it does not bind to the active site. In this case, both statements in the answer are "no", indicating that the correct answer is that the inhibitor does not resemble the substrate and does not bind to the active site.

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Monocotyledonous plants have parallel venation in their leaves, while dicotyledonous plants have net-like venation. Monocots have floral organs in multiples of 3, while dicots have floral organs in multiples of 4 or 5. Therefore, the correct answer is parallel venation; net-like venation; floral organs in multiples of 3; floral organs in multiples of 4 or 5.

The structure labelled X in translation first combines with an amino acid, forming an aminoacyl-tRNA complex. This complex then binds to a codon on the mRNA molecule through its anticodon, allowing for the correct amino acid to be added to the growing polypeptide chain.

The epididymis is responsible for the maturation of sperm. The seminal vesicle produces a fluid that contains fructose, which provides energy for the sperm. The prostate gland also produces a fluid that nourishes and protects the sperm. It contains citric acid, which is important for the overall composition of semen.

During the blood clotting process, prothrombin is converted into thrombin. Thrombin then acts on fibrinogen, converting it into fibrin. Fibrin forms a mesh-like network that traps platelets and red blood cells, forming a blood clot to stop bleeding.

The arrows in the diagram indicate the process of active translocation in the phloem of sucrose from the source to the sink. This means that the plant is actively moving sucrose from where it is produced (source) to where it is needed or stored (sink). This process requires energy and is facilitated by specialized cells called sieve tube elements and companion cells. The phloem is responsible for the transportation of organic nutrients, such as sugars, throughout the plant.

The letters X, Y, and Z indicate the components of a sarcomere, which is the basic unit of a muscle fiber. X represents the dark band, which is also known as the A band and is composed of overlapping myosin filaments. Y represents actin filaments, which are thin filaments that extend into the A band. Z represents the light band, which is also known as the I band and contains only actin filaments. Therefore, the correct answer is the dark band, actin filaments, and myosin filaments.