Exam 3 Biology

Compare the purpose of meiosis to mitosis:

Mitosis produces two genetically identical, diploid (2n) somatic daughter cells for growth and repair. Meiosis produces four genetically unique, haploid (n) gametes for sexual reproduction.

What is the ploidy level for mitosis and meiosis:

Mitosis: starts diploid and ends diploid

Meiosis: starts diploid and ends haploid

Explain the process of crossing over

swaps segments between paired homologous chromosomes, creating new allele combinations

Explain the process of independent assortment in meiosis

randomly aligns and separates chromosome pairs ensuring each gamete get a unique mix of maternal and paternal chromosomes

Explain the process of how meiosis lead to genetic variation in populations:

Crossing over (Prophase 1)-independent assortment (Metaphase 1) - meiosis 2

Explain the process of how fertilization leads to genetic variation in populations:

random fertilization- offspring diversity

What happens if sex chromosomes don't separate properly:

Gametes with abnormal chromosome numbers, such as an extra X or Y, or no sex chromosomes at all will occur

Describe the SRY gene and how it affects crossing over:

a master transcription factor located on the Y chromosome that triggers male development by causing testes to form, overriding the default female pathway

What is asexual reproduction:

involves one parent producing genetically identical offspring; it's fast, effecient, and ideal for stable environments

What is sexual reproduction:

requires two parents to produce genetically unique offspring; provides genetic variation, essential for adaptation, and survival in changing environments

Describe environmental sex determination:

a process where an embryo's sex is decided by incubation temperatures rather than genetics

What effects climate change:

drives rapid feminization, leading to extreme female-biased sex ratios and potential extinction

What is internal fertilization:

involves sperm and egg fusing inside the female's body, common in terrestrial animals for higher success rates

What is external fertilization:

occurs outside the body, usually in aquatic environments, spawning occurs

Explain gene expression plays in differentiation of stem cells:

selectively activating or silencing specific genes, transforming pluripotent cells into specialized tissues

Explain how reproductive tissue differentiates during development:

driven by genetic (SRY) and hormonal signals

What is the hormone involved in differentiation of gonads and other reproductive organs:

testosterone, dihydrotestosterone, and Anti-Mullerian Hormone

Explain the importance of enzymes in metabolic process:

speeds up metabolic reactions by lowering activation energy, ensuring reactions occur fast enough to sustain life

What is Catabolic reactions:

breaks down complex molecules to harvest/release energy

What is anabolic reactions:

uses the energy to build complex molecules

How is it known that glycolysis is a primitive metabolic pathway:

it's universal to almost all living organisms (prokaryotic and eukaryotic), functions in the cytoplasm without oxygen (anaerobic), and mirrors conditions found in early Earth's atmosphere

What are the key products of glycolysis:

2 Pyruvate, 2 Net ATP, and 2 NADH molecules

What stage of aerobic respiration has the glucose molecule been completely broken down:

during the Krebs cycle, or Citric Acid cycle, and it occurs in the mitochondrial matrix (the waste product is carbon dioxide; CO2)

Describe the relationship between electron transport chain and ATP production

The ETC produces ATP by using energy from electrons to pump protons across the mitochondrial membrane

Describe anaerobic metabolic pathways:

They're biochemical processes that generate ATP in the absence of oxygen, or when oxygen supply is insufficient to meet energy needs (EX. Lactic Acid Fermentation and Alcoholic Fermentation)

Name the cell's main energy carrier:

ATP

What is the balanced formula for photosynthesis:

6CO2 + 6H2O ------> C6H12O6 + 6O2

Describe the relationship between pigments, the electromagnetic spectrum, and photosynthesis:

Photosynthetic pigments absorb specific, high-energy wavelengths of the electromagnetic spectrum- mainly blue-violet and red light to drive photosynthesis, while reflecting green light

What is light-dependant reactions:

Inputs: light energy, H2O, ADP+Pi, NADP+

Outputs: O2 (released as waste), ATP, NADPH (Thylakoid Membranes)

What is light-independent reactions:

Inputs: CO2, ATP, NADPH

Outputs: glucose (sugar), ADP+Pi, NADP+ (Stroma)

Describe the transformation of energy in photosynthesis from photons to glucose:

transforms light energy into chemical energy through a two-stage process; photons excite electrons in photosystem II, driving an electron transport chain the generates ATP and NADPH, which act as energy carriers

Compare cyanobacteria and chloroplasts:

both convert light energy into chemical energy (ATP and NADPH) through oxygenic photosynthesis, using water as an electron donor and releasing oxygen; they share similar photosynthetic electron transport chains embedded in thylakoid membranes, reflecting a common evolutionary origin

What is RuBisCo:

an enzyme that helps fix carbon to create sugars; the most abundant protein on Earth)