Jubilee Institute Admission Test · STEM Sciences
Life Sciences and Environmental Biology
78 practice questions, each with the answer and an explanation.
Practise Life Sciences and Environmental Biology now
Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.
All 78 questions
- During aerobic cellular respiration in eukaryotic cells, which metabolic stage produces the largest amount of ATP through oxidative phosphorylation?
- In a monohybrid cross between two heterozygous garden pea plants (Tt x Tt) where tallness (T) is completely dominant to dwarfness (t), what is the theoretical probability of obtaining an offspring tha…
- Which cellular organelle is responsible for post-translational modification, sorting, and packaging of proteins synthesized in the rough endoplasmic reticulum?
- In plant leaves, which specialized epidermal structures regulate transpiration and gas exchange by opening and closing in response to turgor pressure changes?
- What is the complementary mRNA sequence transcribed from the DNA template strand sequence: 3'-TAC GGC TTA CGA ACT-5'?
- In an ecological trophic pyramid, if primary producers fix 10,000 joules of chemical energy through photosynthesis, approximately how much energy is typically transferred to secondary consumers, assum…
- Which hormone produced by the beta cells of the Islets of Langerhans in the pancreas promotes cellular uptake of glucose and glycogenesis in the liver?
- During which phase of meiosis does crossing over (genetic recombination) occur between non-sister chromatids of homologous chromosomes?
- What type of natural selection operates against extreme phenotypic variants and favors intermediate phenotypes in a stable environment?
- Which of the following blood vessels carries oxygen-rich blood directly from the lungs into the left atrium of the human heart?
- In an enzyme-catalyzed reaction, what is the primary mechanism by which an enzyme accelerates the rate of reaction?
- Which biome is characterized by low annual precipitation, extreme diurnal temperature variations, and vegetation dominated by xerophytic succulents and drought-resistant shrubs, as seen in the Jordani…
- Which of the following nitrogenous bases is present in RNA but absent in double-stranded DNA?
- What is the primary function of the myelin sheath that surrounds axons in the mammalian nervous system?
- In the kidney nephron, in which segment does the greatest proportion of mandatory water and solute reabsorption occur from the glomerular filtrate?
- Which kingdom in Whittaker's five-kingdom classification system comprises heterotrophic eukaryotic organisms with cell walls composed primarily of chitin and absorbing nutrients by extracellular diges…
- What ecological term describes an intimate long-term symbiotic interaction in which one organism benefits while the host organism is neither helped nor harmed?
- During photosynthesis in C3 plants, which enzyme catalyzes the initial fixation of atmospheric carbon dioxide to ribulose-1,5-bisphosphate (RuBP)?
- A woman with type AB blood and a man with type O blood have children. What are the possible ABO blood groups of their biological offspring?
- What is the primary role of surfactant secreted by Type II alveolar cells in human lungs?
- In molecular biology, which class of bacterial enzymes recognizes specific palindromic DNA sequences and cleaves phosphodiester bonds at or near these restriction sites?
- Which human cellular organelle possesses its own circular double-stranded DNA genome and 70S ribosomes, supporting the endosymbiotic theory of eukaryotic origin?
- In humans, which endocrine gland is regulated by thyroid-stimulating hormone (TSH) and synthesizes thyroxine (T4) and triiodothyronine (T3) to control basal metabolic rate?
- What type of vascular plant tissue is responsible for the unidirectional translocation of water and dissolved mineral nutrients from roots upward to leaves?
- What occurs during the G1 phase of the eukaryotic somatic cell cycle?
- Which of the following immune cells is primarily responsible for cell-mediated cytotoxicity, recognizing and destroying virus-infected host cells and tumor cells displaying foreign antigens on MHC cla…
- A recessive genetic disorder affects 1 in 2,500 people in a population in Hardy-Weinberg equilibrium. Roughly what fraction of the population are unaffected carriers?
- Two carriers (Cc) of an autosomal recessive condition have a child who shows no symptoms. What is the probability that this child is a carrier?
- In a food chain, 50,000 kJ of energy is fixed by producers. Transfer efficiency is 10 percent from producers to primary consumers, 20 percent from primary to secondary, and 10 percent from secondary t…
- Raising the substrate concentration largely reverses the effect of inhibitor X on an enzyme, and the maximum rate (Vmax) is unchanged. Which description of inhibitor X fits best?
- A coding region of mRNA is 237 nucleotides long (excluding the stop codon). How many amino acids does it code for?
- A coding region of mRNA is 123 nucleotides long (excluding the stop codon). How many amino acids does it code for?
- What is the function of white blood cells?
- A cross produces phenotypes in the ratio 9:3. Out of 204 offspring, how many are expected in the second class?
- A coding region of mRNA is 336 nucleotides long (excluding the stop codon). How many amino acids does it code for?
- A food chain is grass → grasshopper → frog → snake. If the grass fixes 100000 kJ and about 10% of energy passes up each level, how much energy reaches the snake?
- Which gas do plants take in through their stomata for photosynthesis?
- In a sample of double-stranded DNA, 30% of the bases are adenine. What percentage are guanine?
- In pea plants, tall (T) is dominant to short (t). A Tt plant is crossed with a Tt plant. What is the probability that an offspring is showing the dominant phenotype?
- A cell measures 50 μm in reality. In a micrograph it measures 2.5 mm. What is the magnification? (1 mm = 1000 μm)
- A cell measures 20 μm in reality. In a micrograph it measures 4 mm. What is the magnification? (1 mm = 1000 μm)
- Who proposed the theory of evolution by natural selection?
- A cross produces phenotypes in the ratio 8:2. Out of 180 offspring, how many are expected in the second class?
- A coding region of mRNA is 168 nucleotides long (excluding the stop codon). How many amino acids does it code for?
- A cross produces phenotypes in the ratio 6:7. Out of 273 offspring, how many are expected in the second class?
- One bacterial cell divides by binary fission every 20 minutes. How many cells are there after 6 divisions, starting from one cell?
- A cross produces phenotypes in the ratio 9:3. Out of 264 offspring, how many are expected in the second class?
- A cell measures 5 μm in reality. In a micrograph it measures 0.5 mm. What is the magnification? (1 mm = 1000 μm)
- How do vaccines protect against disease?
- Where does fertilisation normally occur in humans?
- In a sample of double-stranded DNA, 33% of the bases are adenine. What percentage are guanine?
- In a population in Hardy–Weinberg equilibrium, 16% of individuals show a recessive trait. What proportion are heterozygous carriers?
- A coding region of mRNA is 114 nucleotides long (excluding the stop codon). How many amino acids does it code for?
- A coding region of mRNA is 282 nucleotides long (excluding the stop codon). How many amino acids does it code for?
- Which colours of light does chlorophyll absorb most strongly?
- What is a group of similar cells working together called?
- In a sample of double-stranded DNA, 31% of the bases are adenine. What percentage are guanine?
- In a reflex arc, which neuron connects the sensory neuron to the motor neuron?
- A food chain is grass → grasshopper → frog → snake. If the grass fixes 50000 kJ and about 10% of energy passes up each level, how much energy reaches the snake?
- A cell measures 5 μm in reality. In a micrograph it measures 0.25 mm. What is the magnification? (1 mm = 1000 μm)
- What is the name of the molecule that supplies energy to cells?
- A cross produces phenotypes in the ratio 4:5. Out of 297 offspring, how many are expected in the second class?
- A coding region of mRNA is 453 nucleotides long (excluding the stop codon). How many amino acids does it code for?
- In a sample of double-stranded DNA, 26% of the bases are adenine. What percentage are guanine?
- What is the main role of the large intestine?
- A coding region of mRNA is 294 nucleotides long (excluding the stop codon). How many amino acids does it code for?
- A cross produces phenotypes in the ratio 7:3. Out of 170 offspring, how many are expected in the second class?
- A coding region of mRNA is 360 nucleotides long (excluding the stop codon). How many amino acids does it code for?
- One bacterial cell divides by binary fission every 20 minutes. How many cells are there after 5 divisions, starting from one cell?
- What does a dominant allele do in a heterozygote?
- Which blood vessels carry blood away from the heart at high pressure?
- Which enzyme, secreted by the salivary glands, begins the digestion of starch in the human mouth?
- Haemophilia is caused by a recessive allele on the X chromosome. A woman who is a carrier and a man without haemophilia have a daughter. What is the probability that the daughter has haemophilia?
- A plant heterozygous for two unlinked genes (AaBb) is crossed with a plant homozygous recessive for both genes (aabb). What fraction of the offspring is expected to show both recessive traits?
- Which type of cell division produces gametes with half the number of chromosomes of the parent cell?
- The population of a fish species in a lake grows rapidly at first and then levels off. What is the term for the largest population that the lake can support over time?
- Which gas, released mainly by burning fossil fuels, makes the largest human contribution to the enhanced greenhouse effect?
- A red blood cell is placed in a salt solution that is much more concentrated than its cytoplasm. What happens to the cell?