Grade 12 Life Sciences - DNA, RNA, and Protein Synthesis

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Flashcards based on Grade 12 Life Sciences Lecture Notes: DNA, DNA Profiling, RNA, and Protein Synthesis

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43 Terms

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What is the function of genes within a chromosome?

To group DNA.

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Approximately how many genes does the human genome contain?

About 35,000 genes.

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What is the role of DNA in genes?

Tells the cell what amino acids to put together to make a protein.

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Describe the structure of DNA.

Two molecules arranged into a ladder-like structure called a Double Helix.

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What are the subunits that make up DNA?

Nucleotides.

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What are the three components of a nucleotide?

Phosphate group, pentose sugar, and a nitrogenous base.

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What forms the backbone of the DNA molecule?

Phosphate and sugar.

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What is the role of the bases in the DNA molecule?

Form the 'rungs' of the DNA ladder.

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What are the four types of nitrogenous bases in DNA?

Adenine (A), Cytosine (C), Thymine (T), and Guanine (G).

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Which base pairs with Adenine (A) in DNA?

Thymine (T).

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Which base pairs with Guanine (G) in DNA?

Cytosine (C).

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Why is complementary base pairing important in DNA structure?

The order of bases in one strand determines the order in the other strand.

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What are codons?

Triplets of bases in DNA.

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What does a gene code for?

A protein.

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What makes each gene unique?

A unique sequence of bases.

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How do proteins relate to phenotype?

Proteins and combinations of proteins give us a unique phenotype.

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Describe the first step of DNA replication.

The double helix unwinds.

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What happens to the hydrogen bonds during DNA replication?

Weak hydrogen bonds between nitrogenous bases break, and two DNA strands unzip (separate).

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What role do the original DNA strands play in replication?

Each original DNA strand serves as a template on which its complement is built.

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What is the outcome of DNA replication?

Two identical DNA molecules, each consisting of one original strand and one new strand.

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Name two significances of DNA replication.

Important for growth, reproduction, and mutations can cause variation.

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What is the main enzyme that catalyzes DNA replication?

DNA polymerase.

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What is DNA Profiling?

A technique used by scientists to distinguish between individuals of the same species using only samples of their DNA.

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What is a DNA fingerprint?

Unique sequence of nucleotides in a segment of DNA.

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What is DNA profiling used for in solving crimes?

To provide evidence that a suspect was present at the crime scene, or to eliminate a suspect from the enquiry.

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Besides solving crimes, what other problems can DNA profiling help with?

Determining a child’s paternity and maternity, which can be used in paternity suits, inheritance cases, and immigration cases.

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Name the three types of RNA.

Messenger RNA (mRNA), Transfer RNA (tRNA), and Ribosomal RNA (rRNA).

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What is the function of mRNA?

Acts as a template for protein synthesis and has the same sequence of bases as the DNA strand that has the gene sequence.

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What is the function of tRNA?

Carries a specific amino-acid and has an anticodon complementary to the mRNA codon.

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What is the function of rRNA?

Makes up an integral part of the ribosome, the protein synthesis machinery in the cell.

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Name two nitrogenous bases present in both DNA and RNA.

Adenine, Cytosine and Guanine.

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Name one difference between DNA and RNA regarding nitrogenous bases.

DNA contains Thymine, while RNA contains Uracil.

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Name two differences between DNA and RNA regarding structure.

DNA is double-stranded, while RNA is single-stranded. DNA contains deoxyribose sugar, while RNA contains ribose sugar.

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What is the function of proteins in living creatures?

Building blocks of cells, control chemical reactions, and transport materials to and from cells.

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What determines the exact function of a protein?

The specific sequence of amino acids in a chain.

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What is a triplet in DNA?

Each sequence of three bases in a DNA strand.

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What does each triplet code for?

One of 20 amino acids, the building blocks of protein.

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Where does transcription occur?

In the nucleus.

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What is the template for the construction of mRNA?

One DNA strand.

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Which base does RNA use instead of thymine?

Uracil (U).

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Where does mRNA attach for protein synthesis?

A ribosome in the cytoplasm.

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What does tRNA bind to?

Amino acids.

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What is an anticodon?

A three-base sequence on tRNA that recognizes a particular mRNA codon.