Biology: Cellular Respiration, Genes & GMOs, Cooking & Digestion

These flashcards cover key concepts from cellular respiration, genetics, cooking methods, and digestive processes.

What are the overall reactants and products of cellular respiration?

Glucose + O₂ → CO₂ + H₂O + ATP.

Where does glycolysis happen, and what does it produce?

In the cytoplasm; produces 2 pyruvate, 2 ATP (net), 2 NADH.

What is the role of oxygen in respiration?

Final electron acceptor in the ETC; forms water.

Compare aerobic vs. anaerobic respiration.

Aerobic = uses O₂ and yields ~36–38 ATP; Anaerobic = no O₂, only 2 ATP via fermentation.

How is photosynthesis 'cellular respiration backward'?

Photosynthesis uses CO₂ and H₂O to make glucose and O₂; respiration uses glucose and O₂ to release CO₂ and H₂O.

What similarities exist between photosynthesis and respiration?

Both have an electron transport chain, pump H⁺ ions, and use ATP synthase.

How many Calories per gram do macronutrients provide?

Carbs = 4 Cal/g; Proteins = 4 Cal/g; Lipids = 9 Cal/g.

Why does the body primarily use glucose for energy?

Easiest and least costly to process; burning fats and proteins requires more energy.

What happens during ketosis?

When carbs are scarce, lipids break down into ketones, which supply energy (especially to the brain).

List two uses of ATP in the body.

Active transport (Na⁺/K⁺ or Ca²⁺ pumps) and Muscle contraction and neural signaling.

What is the Central Dogma?

DNA → mRNA (transcription) → protein (translation) → trait (phenotype).

What is a gene?

A DNA segment that codes for one protein.

Difference between transcription and translation?

Transcription = build mRNA from DNA in nucleus; Translation = use ribosomes and tRNA to assemble amino acids into protein.

Dominant vs. recessive gene?

Dominant = expressed even with one copy; recessive = requires two copies.

Artificial selection vs. genetic modification?

Selection = breeding for traits; GM = direct DNA alteration via lab methods.

Example of a GMO and its benefit.

Golden Rice → added gene for vitamin A production → reduces deficiency.

Define primary, secondary, and tertiary processing.

Primary = raw → ingredients; Secondary = ingredients → food; Tertiary = industrial ready meals.

What is denaturation?

Unfolding of proteins by heat → changes texture, color, and digestibility.

What is the Maillard reaction?

Sugars + amino acids react under heat → browning and flavor.

Advantages and disadvantages of tertiary foods?

Advantages: Cheap, convenient, safe. Disadvantages: High in salt, sugar, and trans fats.

Why did cooking evolve?

Makes food safer and easier to digest by pre-breaking proteins and starches.

Four steps of digestion?

Ingestion → Digestion → Absorption → Elimination.

Mechanical vs. chemical digestion in mouth?

Mechanical = chewing; Chemical = salivary amylase breaks starch.

What does the stomach do?

Uses acid (HCl) and pepsin to break proteins; churns food into chyme.

What enzymes act in the small intestine?

Lipase, protease, carbohydrase (+ bile for fats); Most absorption occurs here.

Large intestine function?

Absorbs water and hosts gut microbes that produce vitamins.

What is the cell membrane made of?

Phospholipid bilayer + proteins + cholesterol + glycoproteins.

Difference between diffusion, osmosis, and facilitated diffusion?

Diffusion = particles high → low; Osmosis = water high → low; Facilitated diffusion = through channel proteins.

What is active transport?

ATP-powered movement low → high (e.g., Na⁺/K⁺ pump).

Define exocytosis and endocytosis.

Exocytosis = release materials; Endocytosis = engulf.

Role of cholesterol in membranes?

Keeps membrane fluid and stable at varying temperatures.

How is glucose from food used for active transport?

Digested → absorbed → cell → respiration makes ATP → ATP powers protein pumps.

Explain how denatured proteins are digested and absorbed.

Cooking unfolds proteins → stomach acid + pepsin break them → amino acids absorbed.

How does a GMO with vitamin A production work?

Inserted gene → transcribed and translated → enzyme increases beta-carotene.

If a meal is highly processed, what changes in digestion and transport?

Rapid absorption of simple carbs and fats, increased insulin response, and heavy ATP use for nutrient transport and storage.