Cell Energy, Respiration, Photosynthesis, Genetics and Evolution

Flashcards on Cell Energy, Respiration, Photosynthesis, Genetics and Evolution

Active Transport

Cells use energy to power the movement of molecules across cell membranes.

Biosynthesis

Cells require energy to drive the synthesis of complex molecules like proteins and DNA.

Homeostasis

Cells need energy to maintain a stable internal environment.

Photosynthesis

The process by which plants convert carbon dioxide, water, and sunlight into glucose and oxygen.

Cellular Respiration

The process by which organisms convert glucose and oxygen into carbon dioxide, water, and ATP.

C6H12O6 + 6O2 → 6CO2 + 6H2O + ~36–38 ATP

Balanced Equation for Cellular Respiration

Oxidation

The loss of electrons from a molecule (e.g., glucose).

Reduction

The gain of electrons by a molecule (e.g., NAD+ becoming NADH).

Glycolysis Location

Cytoplasm

Glycolysis Process

Glucose (6C) is broken down into 2 pyruvate (3C), producing 2 ATP (net) and 2 NADH.

Oxidation of Pyruvate Location

Mitochondrial matrix

Oxidation of Pyruvate Process

Each pyruvate (3C) loses one carbon (as CO2) and becomes acetyl-CoA (2C), reducing NAD+ to NADH.

Citric Acid (Krebs) Cycle Location

Mitochondrial matrix

Citric Acid (Krebs) Cycle Process

Acetyl-CoA (2C) combines with oxaloacetate (4C) to form citric acid (6C), which is oxidized, releasing 2 CO2, producing NADH and FADH2, and generating 1 ATP per cycle. Oxaloacetate is regenerated.

Electron Transport Chain (ETC) Location

Inner mitochondrial membrane

Electron Transport Chain (ETC) Process

NADH and FADH2 donate electrons to the ETC, electrons move through protein complexes, H+ is pumped into the intermembrane space, the H+ gradient drives ATP synthase to produce ~34 ATP. O2 is the final electron acceptor, forming H2O.

Cyanide Poisoning

Cyanide blocks the final protein in the ETC, preventing O2 from accepting electrons, halting ATP production.

Lactic Acid Fermentation

Occurs in muscle cells and some bacteria; pyruvate is converted to lactic acid, NADH is oxidized to NAD+, allowing glycolysis to continue (2 ATP per glucose).

Alcoholic Fermentation

Occurs in yeast and some bacteria; pyruvate is converted to ethanol + CO2, NADH is oxidized to NAD+, allowing glycolysis to continue.

Aerobic Respiration

Requires oxygen, yields 36-38 ATP per glucose, and produces CO2 + H2O + ATP.

Anaerobic Respiration (Fermentation)

Does not require oxygen, yields 2 ATP per glucose, and produces lactic acid or ethanol + CO2.

Yeast Fermentation

Alcoholic fermentation is used for bread and alcohol production.

Carbohydrates

Composed of carbon, hydrogen, and oxygen in a 1:2:1 ratio (e.g., C6H12O6).

Glucose

A monosaccharide with a ring structure; the main source of energy for cells, used in cellular respiration to generate ATP, and a building block for complex carbohydrates.

Monosaccharides

Single sugar units (e.g., glucose, fructose).

Disaccharides

Two monosaccharides linked (e.g., sucrose = glucose + fructose).

Polysaccharides

Long chains of monosaccharides (e.g., starch, cellulose, glycogen).

Dehydration Synthesis

Builds disaccharides/polysaccharides by removing water.

Hydrolysis

Breaks down complex carbohydrates by adding water.

Starch

Energy storage in plants.

Glycogen

Energy storage in animals.

Cellulose

Structural component of plant cell walls.

Autotroph

Makes its own food (e.g., plants).

Heterotroph

Consumes other organisms for food (e.g., animals).

Grana

Stacks of thylakoids in chloroplasts.

Thylakoid

Disc-shaped structures in chloroplasts where light reactions occur.

Thylakoid Membrane

Contains chlorophyll and proteins for the light reactions.

Stroma

Fluid surrounding thylakoids; site of the Calvin cycle.

6CO2 + 6H2O + light → C6H12O6 + 6O2

Photosynthesis Equation

Chlorophyll a

Main pigment in photosynthesis, absorbs red and blue light.

Light Reactions

Convert light energy into ATP and NADPH (in thylakoid membrane).

Calvin Cycle

Uses ATP and NADPH to make G3P sugar from CO2 (in stroma).

NADP+

Accepts electrons and a proton to become NADPH.

RuBP

5-carbon molecule that binds CO2 in the Calvin cycle.

Rubisco

Enzyme that catalyzes the reaction between CO2 and RuBP.

Asexual Reproduction

Involves one parent; offspring are genetically identical.

Sexual Reproduction

Involves two parents; offspring are genetically diverse.

DNA

Molecule that holds genetic information.

Chromatin

Loose form of DNA in interphase.

Chromosome

Condensed, visible DNA during mitosis.

Sister Chromatids

Identical copies of a chromosome, connected by a centromere.

Centromere

The region of a chromosome to which the microtubules of the spindle attach, via the kinetochore, during cell division.

Interphase

G1 (growth), S (DNA replication), G2 (preparation for mitosis).

Mitotic Phase

Mitosis (division of nucleus) and Cytokinesis (division of cytoplasm).

Checkpoints (G1, G2, M)

Controlled by checkpoint proteins (e.g., cyclins, growth factors).

Benign Tumor

Non-cancerous, doesn’t spread.

Malignant Tumor

Cancerous, can invade other tissues.

Metastasis

Spread of cancer cells through blood or lymph to new areas.

Homologous Chromosomes

One from each parent, same genes.

Somatic Cell

Body cell (diploid, 2n).

Gamete

Sex cell (haploid, n).

Diploid (2n)

Two sets of chromosomes (e.g., 46 in humans).

Haploid (n)

One set of chromosomes (e.g., 23 in sperm/egg).

Meiosis I

Homologous chromosomes separate.

Meiosis II

Sister chromatids separate.

Autosomes

Chromosomes not related to sex (pairs 1–22).

Sex Chromosomes

X and Y (pair 23).

XX

Female.

XY

Male.

Crossing Over

Exchange of genetic material between homologs.

Karyotyping

Chromosomes arranged in pairs by size and banding pattern.

Nondisjunction

Failure of chromosomes to separate properly.

Blending Hypothesis

Early idea that traits from parents blend together in offspring.

True-Breeding

Plants that always produce offspring with the same traits.

Hybrid

Offspring of two different true-breeding parents.

P Generation

Parental generation.

F1 Generation

First generation of offspring from the P generation.

F2 Generation

Offspring from a cross of two F1 individuals.

Testcross

A cross between an individual with an unknown genotype and a homozygous recessive individual.

Law of Dominance

One allele can mask another.

Law of Segregation

Alleles separate during gamete formation.

Law of Independent Assortment

Alleles of different genes are inherited independently.

Monohybrid Cross

A cross involving one trait.

Allele

A form of a gene.

Dominant

Allele expressed if present.

Recessive

Allele only expressed if both copies are recessive.

Genotype

Genetic makeup (e.g., AA, Aa).

Phenotype

Physical expression (e.g., tall, short).

Heterozygous

Two different alleles (e.g., Aa).

Homozygous

Two identical alleles (e.g., AA or aa).

Incomplete Dominance

Blending of traits in heterozygous individuals.

Codominance

Both alleles are expressed.

Polygenic Traits

Traits influenced by multiple genes.

Gene Linkage

Genes on the same chromosome inherited together.

Sex-Linked Inheritance

Traits on X or Y chromosomes.

Nitrogenous Base

DNA: Adenine (A), Thymine (T), Cytosine (C), Guanine (G); RNA: Adenine (A), Uracil (U), Cytosine (C), Guanine (G).

DNA

Double-stranded, deoxyribose, A-T base pairing.

RNA

Single-stranded, ribose, A-U base pairing.

Semiconservative Replication

Each new DNA molecule has one old strand and one new strand.

Helicase

Unwinds DNA.