Biology Molecular & Cellular Biology Flashcards

What is the net gain of ATP molecules per glucose molecule during glycolysis alone?

Answer: 2 ATP

Glycolysis yields 4 ATP but consumes 2 ATP in the investment phase, resulting in a net gain of only 2 ATP per glucose.

Which of the following correctly describes the central dogma of molecular biology?

Answer: DNA → RNA → Protein

The central dogma states that genetic information flows from DNA to RNA via transcription and then from RNA to protein via translation.

Which type of bond holds the two strands of a DNA double helix together?

Answer: Hydrogen bonds

Hydrogen bonds between complementary base pairs (A-T and G-C) hold the two antiparallel strands of DNA together.

Sodium-potassium (Na⁺/K⁺) ATPase pumps maintain membrane potential by moving ions how?

Answer: 3 Na⁺ out and 2 K⁺ in per cycle

The Na⁺/K⁺ ATPase expels 3 sodium ions out of the cell and imports 2 potassium ions per ATP hydrolyzed, creating an electrochemical gradient.

Which cellular structure packages and modifies proteins for secretion?

Answer: Golgi apparatus

The Golgi apparatus receives proteins from the ER, modifies them (e.g., glycosylation), sorts, and packages them into vesicles for secretion.

What is the difference between chromatin and chromosomes?

Answer: Chromatin is loosely wound DNA-protein complex; chromosomes are condensed chromatin

Chromatin is the decondensed DNA-histone complex found during interphase, while chromosomes are the highly condensed form visible during cell division.

Which type of RNA carries the genetic information from the nucleus to the ribosome?

Answer: mRNA

Messenger RNA (mRNA) is transcribed from DNA in the nucleus and carries the codon sequence to ribosomes in the cytoplasm for translation.