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HEC USAT Biology Flashcards
59 question-and-answer cards covering Biology as it is examined in HEC USAT. 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.
How does a competitive inhibitor differ from a non-competitive inhibitor?
A competitive inhibitor binds the active site and competes with substrate; a non-competitive inhibitor binds a different (allosteric) site, changing the enzyme's shape.
What generally happens to enzyme activity above its optimum temperature?
The enzyme denatures—its tertiary structure and active site shape are lost—so activity sharply decreases.
In a monohybrid cross between two heterozygous parents (Aa x Aa), what is the genotypic and phenotypic ratio of offspring?
Genotypic ratio 1:2:1 (AA:Aa:aa); phenotypic ratio 3:1 (dominant:recessive).
State Mendel's Law of Segregation.
During gamete formation, the two alleles of each gene separate so that each gamete carries only one allele of the pair.
State Mendel's Law of Independent Assortment.
Alleles of different genes assort independently of one another during gamete formation (applies to genes on different chromosomes).
What is the phenotypic ratio of offspring in a dihybrid cross between two heterozygotes (AaBb x AaBb)?
9:3:3:1.
Define the terms homozygous and heterozygous.
Homozygous means having two identical alleles for a gene (e.g., AA or aa); heterozygous means having two different alleles (e.g., Aa).
According to Chargaff's rule, what are the base-pairing ratios in DNA?
Adenine pairs with Thymine and Guanine pairs with Cytosine, so amount of A = T and G = C (A+G = T+C).
How many hydrogen bonds form between A-T and between G-C base pairs?
Adenine-Thymine form 2 hydrogen bonds; Guanine-Cytosine form 3 hydrogen bonds.
Why is DNA replication described as semi-conservative?
Each new DNA molecule consists of one original (parental) strand and one newly synthesized strand.
What is the role of DNA polymerase and DNA ligase in replication?
DNA polymerase adds new nucleotides to the growing strand (5' to 3'); DNA ligase joins Okazaki fragments on the lagging strand.
What are the two main stages of protein synthesis and where does each occur?
Transcription (DNA to mRNA) occurs in the nucleus; translation (mRNA to protein) occurs at the ribosomes in the cytoplasm.
What is a codon and how many nucleotides does it contain?
A codon is a sequence of three nucleotides on mRNA that codes for one specific amino acid (or a start/stop signal).
What is the function of tRNA in translation?
Transfer RNA carries specific amino acids to the ribosome and matches its anticodon to the complementary mRNA codon.
In the digestive system, which enzyme begins starch digestion and where?
Salivary amylase (ptyalin) begins starch digestion in the mouth.
What is the main site of nutrient absorption in the digestive system, and what feature increases its surface area?
The small intestine; villi and microvilli greatly increase its absorptive surface area.
What is the role of the alveoli in the respiratory system?
Alveoli are the site of gas exchange, where oxygen diffuses into the blood and carbon dioxide diffuses out, due to their thin walls and large surface area.
Trace the path of blood through the four chambers of the heart starting from the body.
Deoxygenated blood enters the right atrium, goes to the right ventricle, to the lungs, returns oxygenated to the left atrium, then the left ventricle pumps it to the body.
Compare arteries and veins in terms of wall thickness and blood pressure.
Arteries have thick, muscular, elastic walls and carry blood at high pressure; veins have thinner walls, valves, and carry blood at low pressure.
What is the function of hemoglobin in red blood cells?
Hemoglobin binds and transports oxygen (as oxyhemoglobin) from the lungs to tissues, and helps carry carbon dioxide back to the lungs.
What are the three main parts of a neuron?
Dendrites (receive impulses), the cell body (soma, contains the nucleus), and the axon (transmits impulses away).
What is the function of the myelin sheath on a neuron?
It insulates the axon and speeds up the conduction of nerve impulses through saltatory conduction at the nodes of Ranvier.
What is the key difference between the nervous system and the endocrine system in coordinating responses?
The nervous system uses electrical impulses for fast, short-lived, localized responses; the endocrine system uses hormones in the blood for slower, longer-lasting, widespread responses.
Which hormone lowers blood glucose, and which gland secretes it?
Insulin lowers blood glucose; it is secreted by the beta cells of the islets of Langerhans in the pancreas.
What this deck covers
The Biology deck follows the HEC USAT Biology syllabus — 6 chapters and 19 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 9.8 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 116 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 HEC USAT deck?
59 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these HEC USAT flashcards free?
Yes. The preview here is free to read with no signup, and the full 59-card deck is free inside the Examius app.
What do the Biology cards cover?
They follow the HEC USAT Biology syllabus — 6 chapters and 19 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.