The mitochondrion (answer B) is the “powerhouse of the cell” because it produces ATP (adenosine triphosphate) through cellular respiration.

• Ribosome → makes proteins, not energy

• Endoplasmic reticulum → helps with protein & lipid synthesis

• Lysosome → breaks down waste

• 🔬 TEAS Biology Question 2:

  If a DNA strand has the sequence:
  5’-ATCGTACG-3’,

  what is the complementary strand?

  A) 5’-TAGCATGC-3’
  B) 3’-TAGCATGC-5’
  C) 5’-UAGCAUGC-3’
  D) 3’-UAGCAUGC-5’

  ---

  👉 What’s your answer?

  (We’ll check and explain before moving to Question 3.)

  If you’d like, I can also show you a shortcut method to always find complementary DNA strands. Would you like me to include that in the explanation?

  You said:

  b

  MathGPT Pro | MathGPTPro said:

  ✅ Correct again! 🎉

  The complementary DNA strand is 3’-TAGCATGC-5’ (answer B).

  Here’s why:

  • DNA follows base-pairing rules:

    • A ↔ T

    • C ↔ G

  • The given strand is 5’-ATCGTACG-3’.

  • Pairing each base:

    • A → T

    • T → A

    • C → G

    • G → C

    • T → A

    • A → T

    • C → G

    • G → C

  That gives: TAGCATGC.
  Since DNA strands are antiparallel, the complementary strand must be written 3’ → 5’.