HESI Biology - set 2

Dominant allele

An allele that is expressed when present

Recessive allele

An allele expressed only when two copies are present

Homozygous

Two identical alleles for a trait

Heterozygous

Two different alleles for a trait

Genotype

The genetic makeup of an organism

Phenotype

The physical expression of a trait

Punnett square tool

Predicts possible offspring genotypes

Probability of heterozygous x heterozygous recessive offspring

25% recessive, 50% heterozygous, 25% dominant

Carrier

Individual with one recessive allele who does not show the trait

Purpose of photosynthesis

Convert sunlight into glucose

Where photosynthesis occurs

Chloroplasts

Reactants of photosynthesis

Carbon dioxide and water

Products of photosynthesis

Glucose and oxygen

Purpose of cellular respiration

Break down glucose to make ATP

Where cellular respiration occurs

Mitochondria

Reactants of cellular respiration

Glucose and oxygen

Products of cellular respiration

Carbon dioxide, water, ATP

Relationship between photosynthesis and respiration

Products of one are reactants of the other

Prokaryotic cell

Cell without a nucleus

Eukaryotic cell

Cell with a nucleus

Size comparison

Eukaryotes are larger than prokaryotes

Examples of prokaryotes

Bacteria

Examples of eukaryotes

Plants, animals, fungi, protists

Organelle presence

Eukaryotes have membrane-bound organelles; prokaryotes do not

Homeostasis

Maintaining a stable internal environment

Example of homeostasis

Body temperature regulation

Negative feedback

Mechanism that reverses a change to maintain balance

Positive feedback

Mechanism that amplifies a change

Role of the hypothalamus

Controls many homeostasis functions

Food chain

Shows how energy moves from one organism to another

Producer

Organism that makes its own food (plants)

Primary consumer

Herbivore that eats producers

Secondary consumer

Carnivore that eats herbivores

Tertiary consumer

Top predator in a food chain

Decomposer

Breaks down dead organisms and recycles nutrients

Energy flow rule

Energy decreases at each trophic level

10% rule

Only 10% of energy is passed to the next level

Ecosystem

Community of organisms and their environment