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🇵🇰 ETEA Medical Test · flashcards
ETEA Medical Test Biology Flashcards
56 question-and-answer cards covering Biology as it is examined in ETEA Medical Test. 24 of them are printed below, taken from across the deck — no signup, no paywall on the preview.
24 sample cards from the Biology deck
Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.
What type of bond links fatty acids to glycerol in a lipid?
An ester bond links each fatty acid to glycerol, formed by a condensation (esterification) reaction with the removal of a water molecule.
What is the structure of a phospholipid and why is it important?
A phospholipid has a glycerol backbone, two fatty acid tails (hydrophobic), and a phosphate-containing head (hydrophilic), making it amphipathic. This dual nature allows phospholipids to form the bilayer of cell membranes.
Give three biological functions of lipids.
Lipids serve as long-term energy storage (yielding ~9 kcal/g, more than carbohydrates), structural components of membranes (phospholipids), thermal insulation and cushioning, and precursors of steroid hormones and vitamins (e.g., cholesterol, vitamin D).
What is cholesterol and what are its functions?
Cholesterol is a steroid lipid with a four-ring structure. It is a component of animal cell membranes (regulating fluidity), and a precursor for steroid hormones, bile salts, and vitamin D.
What are the three components of a nucleotide?
A nucleotide consists of a pentose (5-carbon) sugar, a nitrogenous base, and a phosphate group.
Compare the structure of DNA and RNA.
DNA is double-stranded, contains deoxyribose sugar, and uses the base thymine. RNA is single-stranded, contains ribose sugar, and uses uracil instead of thymine. Both contain adenine, guanine, and cytosine.
What are the purine and pyrimidine bases in DNA?
Purines (double-ring): adenine (A) and guanine (G). Pyrimidines (single-ring): cytosine (C) and thymine (T). In RNA, thymine is replaced by uracil (U), also a pyrimidine.
State the base-pairing rules in DNA and the type of bond involved.
Adenine pairs with thymine (A-T) via two hydrogen bonds, and guanine pairs with cytosine (G-C) via three hydrogen bonds. This is complementary base pairing (Chargaff's rule: A=T, G=C).
What bond joins nucleotides together in a nucleic acid strand?
A phosphodiester bond joins nucleotides, linking the phosphate group of one nucleotide to the sugar (3' carbon) of the next, forming the sugar-phosphate backbone.
What is ATP and why is it important?
ATP (adenosine triphosphate) is a nucleotide consisting of adenine, ribose, and three phosphate groups. It is the universal energy currency of the cell; energy is released when the terminal high-energy phosphate bond is hydrolyzed to form ADP + inorganic phosphate.
Why is water described as a polar molecule, and what property does this give it?
In water, oxygen is more electronegative than hydrogen, creating a partial negative charge on oxygen and partial positive on hydrogen. This polarity allows hydrogen bonding between molecules and makes water an excellent solvent (the 'universal solvent').
What is the difference between cohesion and adhesion in water?
Cohesion is the attraction between water molecules themselves (due to hydrogen bonding), important for surface tension and water transport in plants. Adhesion is the attraction between water molecules and other surfaces, contributing to capillary action.
Why does water's high specific heat capacity matter biologically?
Water requires a large amount of heat to change temperature because hydrogen bonds absorb energy. This high specific heat capacity allows water to act as a temperature buffer, stabilizing the temperature of cells, organisms, and aquatic environments.
Define an enzyme and explain the 'lock and key' model of enzyme action.
An enzyme is a biological catalyst (usually a protein) that speeds up reactions by lowering activation energy. In the lock and key model, the substrate (key) has a shape exactly complementary to the rigid active site (lock) of the enzyme, so only the specific substrate fits.
What is the 'induced fit' model of enzyme action and how does it differ from the lock and key model?
In the induced fit model (Koshland), the active site is not rigid but flexible; binding of the substrate causes the active site to change shape slightly to fit snugly around the substrate. Unlike the lock and key model, the enzyme is moulded around the substrate.
How does an enzyme speed up a reaction in terms of activation energy?
An enzyme lowers the activation energy (the minimum energy needed for a reaction to proceed) by stabilizing the transition state. This allows the reaction to occur faster and at lower temperatures, without the enzyme being consumed.
How do temperature and pH affect enzyme activity?
Each enzyme has an optimum temperature and pH at which activity is maximal. Below the optimum, activity is slow; above the optimum (or at extreme pH), the enzyme denatures and loses function. Most human enzymes have an optimum around 37 degrees Celsius and pH near 7.
How does substrate concentration affect the rate of an enzyme-catalyzed reaction?
As substrate concentration increases, the reaction rate increases proportionally until all active sites are occupied (saturation point). Beyond this, the rate plateaus at Vmax (maximum velocity) because the enzyme is the limiting factor.
Compare competitive and non-competitive enzyme inhibition.
Competitive inhibitors resemble the substrate and bind to the active site, blocking substrate binding; their effect can be overcome by increasing substrate concentration. Non-competitive inhibitors bind to an allosteric site (other than the active site), changing the enzyme's shape; their effect is not reversed by adding more substrate.
What is the overall balanced equation for photosynthesis?
6CO2 + 6H2O + light energy --> C6H12O6 + 6O2 (carbon dioxide plus water, using light energy and chlorophyll, produces glucose and oxygen).
What are the two main stages of photosynthesis and where do they occur?
The light-dependent reactions occur in the thylakoid membranes of the chloroplast and produce ATP, NADPH, and oxygen. The light-independent reactions (Calvin cycle) occur in the stroma and use ATP and NADPH to fix carbon dioxide into glucose.
What is produced during the light-dependent reactions of photosynthesis?
The light-dependent reactions produce ATP (via photophosphorylation), NADPH (reduced electron carrier), and oxygen (from the photolysis/splitting of water).
What is the role of chlorophyll in photosynthesis?
Chlorophyll is the green pigment in chloroplasts that absorbs light energy (mainly red and blue wavelengths, reflecting green) and converts it into chemical energy, exciting electrons to drive the light-dependent reactions.
What happens in the Calvin cycle (light-independent reactions)?
In the stroma, carbon dioxide is fixed by combining with RuBP (catalyzed by the enzyme RuBisCO) and, using ATP and NADPH from the light reactions, is reduced to form glucose. This is the carbon fixation stage and does not directly require light.
What this deck covers
The Biology deck follows the ETEA Medical Test Biology syllabus — 11 chapters and 36 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 5.1 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 219 characters, which is long enough to carry the reasoning and short enough to say out loud.
A deck like this earns its keep on the second and third pass. Read the syllabus first so you know the shape of the subject, then use the cards to find the specific facts that have not stuck.
Biology flashcards FAQ
How many Biology flashcards are in this ETEA Medical Test deck?
56 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these ETEA Medical Test flashcards free?
Yes. The preview here is free to read with no signup, and the full 56-card deck is free inside the Examius app.
What do the Biology cards cover?
They follow the ETEA Medical Test Biology syllabus — 11 chapters and 36 topics — so the questions track what is actually examinable.
How should I use these flashcards?
Read the syllabus first so you know the shape of the subject, then drill the deck. Examius schedules each card with spaced repetition, so cards you keep missing come back sooner and ones you know drift further apart.