CELL STRUCTURE & BIOCHEMISTRY
Which biomolecule is responsible for storing genetic information?
Nucleic acids (DNA)
During which phase is DNA copied?
S phase (interphase)
What is a mutation?
A change in the DNA sequence
Two heterozygous parents (Aa × Aa) are crossed.
👉 What is the probability of aa offspring?
25%
What is evolution?
Change in populations over time
What is natural selection?
Individuals with beneficial traits survive and reproduce more
What is photosynthesis?
Making glucose using sunlight
What system controls the body?
Nervous system
What is biodiversity?
Variety of life
A molecule speeds up chemical reactions in a cell. What type of biomolecule is it and why?
Protein; enzymes are proteins that lower activation energy
A cell continues dividing even with DNA damage. What is the likely outcome?
Cancer due to uncontrolled cell division
What type of mutation adds or removes nucleotides and shifts the reading frame?
Frameshift (insertion or deletion)
A red flower and white flower produce pink offspring.
👉 What inheritance pattern is this?
Incomplete dominance
Fossils found deeper in rock layers are older.
👉 What principle explains this?
Law of superposition
Why do individuals NOT evolve through natural selection?
Evolution occurs in populations over generations
What is cellular respiration?
Breaking down glucose for energy
What system transports oxygen?
Circulatory system
What is mutualism?
Both benefit
Why can eukaryotic cells carry out more complex processes than prokaryotic cells?
They have membrane-bound organelles that separate and specialize functions
What controls which genes are expressed in a cell?
Regulatory signals and cell environment
How does DNA determine an organism’s traits?
DNA codes for proteins that control traits
DNA → RNA → Protein
If a trait is recessive, why can it appear in offspring even if neither parent shows it?
Both parents can be carriers (heterozygous)
Give one type of evidence for evolution
Fossils / DNA / homologous structures
What is genetic drift?
Random change in allele frequency
What do enzymes do?
Speed up reactions by lowering activation energy
Why do systems work together?
Maintain homeostasis
What happens when biodiversity decreases?
Stability decreases
Both cells and viruses contain genetic material. Why are only cells considered living?
Cells can carry out all life processes; viruses cannot without a host
What is the main purpose of the cell cycle?
Growth, repair, and reproduction of cells
Why does translation occur at ribosomes instead of the nucleus?
Ribosomes assemble amino acids into proteins
How does independent assortment increase genetic diversity?
Chromosomes are randomly separated into gametes
What are homologous structures?
Same structure, different function (common ancestry)
What is gene flow?
Movement of genes between populations
Compare photosynthesis and respiration.
Opposite processes (energy stored vs released). The products of one reaction is the reactants of the other
How do plant systems transport water?
Xylem
What is the role of producers?
Start energy flow
A cell cannot regulate what enters and leaves. Which structure is failing and what is the consequence?
Cell membrane; loss of homeostasis leads to cell dysfunction or death
Why might a loss of differentiation be linked to cancer?
Cells lose specialization and divide uncontrollably instead of performing functions
Why are frameshift mutations usually more harmful than substitution mutations?
They change the entire amino acid sequence
Why does meiosis produce genetically unique gametes while mitosis does not?
Meiosis includes crossing over and independent assortment; mitosis produces identical cells
How do fossils support evolution?
Show changes in organisms over time
Why does natural selection act on phenotypes but affect genotypes?
Traits determine survival, but genes are passed on
Explain how matter is conserved on photosynthesis and cellular respiration
Matter is conserved in photosynthesis and cellular respiration because the same atoms (carbon, hydrogen, and oxygen) are rearranged to form new molecules, rather than being created or destroyed.
Why is system interaction necessary for survival?
Systems depend on each other to perform essential functions
How does disrupting the carbon or nitrogen cycle affect ecosystems?
Disrupting the carbon or nitrogen cycle affects ecosystems by altering the availability of essential nutrients, which disrupts energy flow, population sizes, and overall ecosystem stability.