DNA, RNA, and Protein Synthesis Study Guide Review

Why is DNA replication called "semi-conservative"?

• Only half of the original DNA is kept
• Each new DNA molecule has one old strand and one new strand
• The process saves energy by reusing old DNA strands
• Only half of the cell's DNA gets copied

If the DNA sequence changes from ATGCTA to ATGTTA, what will likely happen?

• Nothing, because both sequences make the same amino acids
• The cell will stop making proteins completely
• One amino acid in the protein might be different
• The DNA won't be able to make copies of itself

How are mRNA and tRNA different in what they do?

• mRNA carries genetic instructions while tRNA carries amino acids
• mRNA stays in the nucleus while tRNA works outside it
• mRNA has one strand while tRNA has two strands
• mRNA uses uracil while tRNA uses thymine

Why does DNA need mRNA to carry information to ribosomes?

• Because DNA can break easily if it moves
• Because DNA is too big to leave the nucleus
• Because ribosomes can only understand RNA
• Because DNA needs to stay safe in the nucleus

If a DNA strand reads TACGGA, what would the matching mRNA sequence be?

• AUGCCU
• TACGGA
• ATGCCT
• UACGGA

Which comparison best shows how DNA relates to proteins?

• Like a recipe book and the meal it makes
• Like a key fitting into a lock
• Like a map leading to a destination
• Like a seed growing into a tree

What happens if tRNA brings the wrong amino acids to the ribosome?

• The ribosome won't accept the amino acid
• The whole process will stop right away
• The protein will be made with mistakes
• The mRNA will fix the mistake

How does the cell make sure DNA copies are accurate?

• By keeping multiple DNA copies
• By using special enzymes that check for mistakes
• By making several copies of DNA
• By pure chance

Why can mutations sometimes be good for organisms?

• They always help organisms survive better
• They create different versions of genes that might help species adapt
• They repair damaged DNA
• They make proteins work better

What do sugar and phosphate molecules do in DNA?

• They carry genetic information
• They create the basic structure that holds DNA together
• They connect nucleotides to each other
• They determine which bases pair up