unit 5 to 7

Photosynthesis

Process that converts light energy into chemical energy stored in glucose.

Overall equation of photosynthesis

6CO2 + 6H2O + light → C6H12O6 + 6O2.

Autotroph

Organism capable of producing its own food.

Photoautotroph

Organism that uses sunlight to synthesize carbohydrates.

Heterotroph

Organism that obtains energy by consuming other organisms.

Chloroplast

Organelle where photosynthesis takes place.

Thylakoid

Flattened membrane sac containing chlorophyll.

Granum

Stack of thylakoids.

Stroma

Fluid surrounding thylakoids where the Calvin Cycle occurs.

Chlorophyll

Main pigment involved in photosynthesis.

Electromagnetic spectrum

Entire range of electromagnetic radiation.

Visible light

Portion of spectrum used in photosynthesis.

Blue light

High-energy light efficiently absorbed by chlorophyll.

Red light

Light strongly absorbed during photosynthesis.

Green light

Mostly reflected by plants.

Light-dependent reactions

Reactions that capture sunlight to produce ATP and NADPH.

Location of light reactions

Thylakoid membrane.

Photosystem II

First photosystem activated during light reactions.

Photosystem I

Second photosystem involved in NADPH production.

Photolysis

Splitting of water molecules.

Products of photolysis

Oxygen, electrons and hydrogen ions.

Electron transport chain

Series of proteins transferring electrons to produce ATP.

Chemiosmosis

Process that uses proton gradients to synthesize ATP.

ATP synthase

Enzyme that produces ATP.

ATP

Main energy currency of the cell.

NADPH

Electron carrier used in the Calvin Cycle.

Calvin Cycle

Light-independent reactions producing carbohydrates.

Location of Calvin Cycle

Stroma.

Carbon fixation

Attachment of CO2 to RuBP.

RuBP

Five-carbon molecule involved in carbon fixation.

Rubisco

Enzyme that catalyzes carbon fixation.

Reduction phase

Step where ATP and NADPH are used to produce G3P.

Regeneration phase

Step that regenerates RuBP.

G3P

Three-carbon sugar produced by the Calvin Cycle.

Photosynthesis importance

Provides oxygen and forms the base of most food chains.

Genome

Entire genetic complement of an organism.

Gene

Segment of DNA coding for proteins or RNA.

Diploid

Cell containing two chromosome sets (2n).

Haploid

Cell containing one chromosome set (n).

Human somatic cells

Contain 46 chromosomes.

Human gametes

Contain 23 chromosomes.

Homologous chromosomes

Chromosomes with genes in the same order inherited from different parents.

Cell cycle

Orderly sequence of cell growth and division.

Interphase

Period including G1, S and G2 phases.

G1 phase

Cell growth and normal metabolism.

S phase

DNA replication occurs.

G2 phase

Preparation for mitosis.

Mitosis

Process producing two genetically identical daughter cells.

Prophase

Chromosomes condense and spindle begins forming.

Prometaphase

Nuclear envelope breaks down and spindle attaches to kinetochores.

Metaphase

Chromosomes align at the metaphase plate.

Anaphase

Sister chromatids separate.

Telophase

New nuclei form.

Cytokinesis

Division of cytoplasm.

Cleavage furrow

Animal cell cytokinesis.

Cell plate

Plant cell cytokinesis.

Checkpoint

Control mechanism regulating cell cycle progression.

G1 checkpoint

Determines if cell enters division.

G2 checkpoint

Ensures DNA replication is complete.

Metaphase checkpoint

Checks spindle attachment.

Cancer

Uncontrolled cell division caused by mutations.

Proto-oncogene

Normal gene regulating cell growth.

Oncogene

Mutated proto-oncogene promoting uncontrolled growth.

Tumor suppressor gene

Gene preventing excessive cell division.

Binary fission

Cell division mechanism in bacteria.

FtsZ

Protein directing bacterial cytokinesis.

Septum

Partition forming between bacterial daughter cells.

Sexual reproduction

Produces genetically unique offspring.

Asexual reproduction

Produces genetically identical offspring.

Advantage of sexual reproduction

Increased genetic variation.

Meiosis

Process producing four genetically unique haploid cells.

Meiosis I

Reduction division separating homologous chromosomes.

Meiosis II

Division separating sister chromatids.

Interphase before meiosis

DNA replication occurs.

Prophase I

Most important phase of meiosis.

Synapsis

Pairing of homologous chromosomes.

Tetrad

Four chromatids joined together.

Crossing over

Exchange of DNA between homologous chromosomes.

Chiasmata

Physical location where crossing over occurs.

Metaphase I

Homologous pairs align randomly.

Independent assortment

Random orientation of homologous chromosomes.

Anaphase I

Homologous chromosomes separate.

Telophase I

Two haploid cells form.

Interkinesis

Resting period between meiosis I and II.

Anaphase II

Sister chromatids separate.

Result of meiosis

Four genetically unique haploid cells.

Gamete

Haploid reproductive cell.

Fertilization

Fusion of sperm and egg restoring diploid number.

Zygote

Diploid cell formed after fertilization.

Nondisjunction

Failure of chromosomes to separate properly.

Aneuploid

Abnormal chromosome number.

Trisomy

Extra chromosome.

Monosomy

Missing chromosome.

Down syndrome

Trisomy 21.

Turner syndrome

XO chromosome composition.

Klinefelter syndrome

XXY chromosome composition.

Barr body

Inactive X chromosome in females.

X inactivation

Process silencing one X chromosome.

Inversion

Chromosome segment rotates and reinserts.

Translocation

Chromosome segment moves to another chromosome.