Grade 11 bio exam review

What is taxonomy?

Taxonomy is the science of classification that involves naming, identifying, and classifying species.

What is the hierarchy of taxa?

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

What is binomial nomenclature?

A two-name Latin naming system for organisms using Genus and species, developed by Carl Linnaeus.

What are the rules of binomial nomenclature?

Genus is capitalized, species is lowercase, and the name is italicized or underlined.

How does a dichotomous key work?

It helps identify things by asking a series of yes/no questions that lead you step-by-step to the correct name.

What are the two viral cycles?

Lytic cycle: virus takes over the host and causes lysis. Lysogenic cycle: viral DNA integrates into host DNA and replicates silently until triggered.

What is the difference between lytic and lysogenic cycles?

Lytic destroys the host cell immediately; lysogenic hides within the DNA and activates later.

What is a vaccine?

A vaccine contains weakened or dead pathogens to stimulate immunity without causing disease.

What are the three domains of life?

Bacteria, Archaea, Eukarya.

What are the six kingdoms?

Eubacteria, Archaebacteria, Protista, Fungi, Plantae, Animalia.

What are the differences between prokaryotes and eukaryotes?

Prokaryotes have no nucleus or membrane-bound organelles -simple cells; eukaryotes do -complex cells.

How do you read a phylogenetic tree?

Organisms that share a more recent common ancestor are more closely related.

What is biodiversity?

The variety and number of life forms on Earth.

Why is biodiversity important?

Essential for ecosystem stability, human survival, and environmental health.

What causes biodiversity to decline?

Habitat loss, climate change, pollution, invasive species, overexploitation.

How can humans restore biodiversity?

Reforestation, reduce pollution, fight climate change, stop overexploitation, protect habitats.

What is a genotype?

The genetic makeup of an organism (e.g., Bb or BB).

What is a phenotype?

The observable traits of an organism (e.g., brown eyes).

What is the difference between dominant and recessive?

Dominant traits show with one allele (A), recessive traits only show with two alleles (aa).

What is homozygous?

An organism with two identical alleles (e.g., BB or bb).

What is heterozygous?

An organism with two different alleles (e.g., Bb).

What is a Punnett square used for?

To predict the genotypes and phenotypes of offspring from genetic crosses.

What is a monohybrid cross?

A cross involving one trait (e.g., flower color).

What is a dihybrid cross?

A cross involving two traits (e.g., seed shape and seed color).

What is codominance?

Both alleles are expressed equally in the phenotype (e.g., AB blood type).

What is blood typing?

A type of codominance where A and B are codominant and O is recessive.

What are the three main stages of the cell cycle?

Interphase (growth), Mitosis (nuclear division), Cytokinesis (cell splits).

What is mitosis?

Cell division resulting in two genetically identical diploid cells.

What is meiosis?

Cell division producing four genetically different haploid gametes.

What is nondisjunction?

The failure of homologous chromosomes to separate properly during meiosis.

What is spermatogenesis?

The formation of sperm cells through meiosis in males.

What is oogenesis?

The formation of egg cells through meiosis in females.

When does crossing over occur?

During prophase I of meiosis; it increases genetic variation.

What is natural selection?

The process where individuals with favorable traits survive and reproduce more successfully.

What is gene flow?

The movement of alleles between populations due to migration.

What is genetic drift?

Random changes in allele frequencies, especially in small populations.

What is the bottleneck effect?

A large reduction in population size due to a disaster, reducing genetic diversity.

What is the founder effect?

A new population started by a few individuals has reduced genetic variation.

What is stabilizing selection?

Favors average traits, reducing extremes.

What is disruptive selection?

Favors both extreme traits, selecting against the average.

What is directional selection?

Favors one extreme trait over the other.

What are mutations?

Changes in DNA that create genetic variation; can be harmful, neutral, or beneficial.

What causes antibiotic resistance?

Mutations or gene transfer that allow bacteria to survive antibiotics.

What are homologous structures?

Similar structure, different function – shows common ancestry.

What are analogous structures?

Different structure, same function – no common ancestry.

What is gradual equilibrium?

Species evolve slowly over long periods.

What is punctuated equilibrium?

Species evolve slowly, with rapid bursts of change.

What are prezygotic barriers?

Prezygotic barriers prevent fertilization before a zygote forms. Examples:

• Behavioral isolation – Different mating behaviors (e.g., frog mating calls)

• Temporal isolation – Mate at different times (e.g., early vs late bloomers)

• Ecological isolation – Live in different habitats (e.g., birds at different elevations)

• Mechanical isolation – Incompatible reproductive parts (e.g., damselflies)

• Gametic isolation – Sperm and egg can't fuse (e.g., marine animals)

What are postzygotic barriers?

Barriers after fertilization that prevent viable, fertile offspring (e.g., Zygotic mortality,Hybrid inviability,Hybrid infertility)

What are human-driven selective pressures?

Selective breeding, habitat destruction, climate change, antibiotic use.

What is the main function of the digestive system?

Break down food to absorb nutrients for energy and body repair.

What is peristalsis?

Wave-like muscle contractions that move food through the digestive tract.

What is the path of food through the digestive system?

Mouth → Esophagus → Stomach → Small Intestine → Large Intestine → Rectum → Anus.

Where does most nutrient absorption occur?

In the small intestine, especially the villi.

What are the parts of the respiratory system?

Nasal cavity, pharynx, larynx, trachea, bronchi, lungs, alveoli, diaphragm.

What happens during inhalation?

Diaphragm contracts, lungs expand, air flows in, chest moves upand out, increasing lung volume and decreasing pressure, intercostal muscles contract, moving the ribcage up and out.

What happens during exhalation?

Diaphragm relaxes, lungs deflate, air is pushed out,chest moves back down, intercostal muscles relax, moving the ribcage down and in.

Where does gas exchange occur?

In the alveoli between the air and capillaries.

What gas lowers blood pH and triggers breathing?

Carbon dioxide (CO₂).

What is aerobic respiration?

Cellular respiration using oxygen; produces 36 ATP.

What is anaerobic respiration?

Occurs without oxygen; produces less energy.

What is lactic acid fermentation?

A type of anaerobic respiration where glucose is broken down without oxygen, producing lactic acid and energy (ATP); occurs in muscle cells during intense exercise.

What is ethanol fermentation?

A type of anaerobic respiration where glucose is broken down without oxygen, producing ethanol, carbon dioxide, and energy (ATP); occurs in yeast and some bacteria.

What are the main parts of the circulatory system?

Heart, blood vessels (arteries, veins, capillaries), and blood.

What are the four components of blood?

Red blood cells, white blood cells, platelets, plasma.

What is blood pressure?

The force of blood against artery walls.

What is systolic pressure?

Pressure when the heart contracts (top number).

What is diastolic pressure?

Pressure when the heart relaxes (bottom number).

What happens to blood pressure during exercise?

It increases to deliver more oxygen to muscles.

What are arteries?

Carry blood away from the heart; thick walls; high pressure.

What are veins?

Carry blood to the heart; have valves; lower pressure.

What are capillaries?

Tiny vessels where gas and nutrient exchange occur.

What happens during heavy bleeding?

Blood vessels constrict, heart rate increases, clotting is triggered.

How are body systems connected?

Digestive absorbs nutrients, respiratory brings in oxygen, circulatory carries both to cells for energy and removes waste like carbon dioxide.

What is the purpose of leaves?

Photosynthesis – they capture sunlight and exchange gases.

What is the purpose of stems?

Support the plant and transport water and nutrients.

What is the purpose of roots?

Anchor the plant and absorb water and minerals from soil.

What is the function of the cuticle?

Waxy coating that prevents water loss.

What does the upper epidermis do?

Provides protection and allows light through to photosynthetic cells.

What is the palisade mesophyll?

Tightly packed cells with many chloroplasts for photosynthesis.

What is the spongy mesophyll?

Loosely packed cells that allow gas exchange.

What are stomata?

Pores on the leaf surface for gas exchange.

What do guard cells do?

Open and close the stomata to regulate gas exchange and water loss.

What is transpiration?

Loss of water through stomata; helps pull water up from roots.

What are ideal crop growth conditions?

Moist, nutrient-rich soil, proper light, air circulation, and temperature.

What can gardeners do to promote plant health?

Mulching, watering properly, rotating crops, using compost, managing pests.