DNA Flashcards
What are the four bases in DNA?
- Adenine
- Cytosine
- Guanine
- Thymine
What is Adenine always paired with?
- Thymine
What is cytosine always paired with?
- Guanine
What shape is DNA?
- Double Helix
State the basic structure of DNA?
What is RNA?
- RNA nucleotides are joined to form a single strand
How does RNA differ from DNA?
- RNA is a single stranded while DNA is double stranded
- RNA has a sugar called ribose while DNA has a sugar called deoxyribose
- RNA has the base uracil while DNA has the base thymine
What are the two type of RNA you need to know about?
- Messenger RNA
- Transfer RNA
What is messenger RNA?
- It copies the sequence of bases of a section of the DNA
- This process is called transcription
What is the transfer RNA?
- The tRNA picks up specific amino acids and are joined together in a specific order to make a protein
- This process is called translation
How do we abriviate messenger RNA and transfer RNA?
- mRNA
- tRNA
Define a gene?
- A length of DNA which codes for a protein
How many choromasomes are in a human? (not sex cells)
46
How many chormasomes are in sex cells of one human?
- 23
What are the two letters for being female?
- XX
What are the two letters for being male?
- XY
What is a diploid cell?
- Contains two copies of each of their 23 chromasomes
What is a hapoloid cell?
- Only contains one copy of each chromosome
What are the two types of cell division?
- Mitosis
- Meiosis
What is meiosis used for?
- It produces haploid gametes which are not genetically identical
- Meiosis is only used for sexual reproduction
What is mitosis used for?
- Produces genetically identical daughter cells which are diploid
- Mitosis is used for growth, repair and asexual reproduction
What are some differences in the processes of Mitosis and Meiosis?
- Mitosis produces genetically identical daughter cells
- Meiosis produces non identical daughter cells
- Mitosis produces two cells
- Meiosis produces four cells
- Mitosis involves one division
- Meiosis involves two divisions
- Mitosis produces diploid cells
- Meiosis produces haploid cells
What are the differences in Mitosis and Meiosis roles?
- Mitosis generates all adult cells except gametes
- Meiosis only generates gametes
- Mitosis occurs throught human body
- Meiosis occurs in ovary and testis
- Mitosis used for asexual reproduction
- Meiosis used for sexual reproduction
State the process of Mitosis?
State the process of meiosis?
What is variation?
- The diffferences between individuals
What are the two main types of variation?
- Continuous: e.g height
- Discontinuous: e.g blood group
What can varation be caused by?
- Genetic
- Enviromental
What causes a mutation?
- Variation in genes is the result of sexual reproduction
What are the different effects of a mutation?
- Positive
- Neutral
- Negative
What is a genotype?
- The allele combination
What is a phenotype?
- Characteristic of the alleles produced
What are the two stages for making proteins?
- Transcription (Uses mRNA)
- Translation (Uses tRNA)
Why do we need transcription in protein synthesis?
- Proteins are made in the ribosomes. DNA is found in the nucleus but can’t move out cause it is really big
- mRNA is shorter and only a single strand
- It also uses uracil instead of thymine
How does Transcription work?
- The RNA polymerase binds to a region of non-coding DNA
- Two DNA strands unzip and the RNA polymerase moves along one of the strands of the DNA
- It uses coding DNA in the gene as a template to make the mRNA. Base pairing between the DNA and RNA ensures that the mRNA is complementary to the gene
- mRNA mvoes out of nucleus and joins with ribosomes in cytoplasm
How do you write GTTGTTTCCG in mRNA form?
- GUUGUUUCCG
How does Translation work?
- The mRNA strand travels through the cytoplasm then passes through ribosome.
- Every 3 mRNA bases line up with a complimentary 3 bases from the tRNA
- tRNA transports specific amino acids to the ribosomes according to the code
- A chain of amino acids forms a polypeptide.
- Folded into correct shape to become a protein
What is a codon?
- A sequence of 3 bases in a gene
What is an anticodon?
- It is part of the t-RNA structure and complementary to a codon for the amino acid
- It ensures the correct order of amino acids are brought to the ribosome
