Compendium 11. DNA Flashcards
What are genes?
Genes are the codes for proteins
Describe the structure of DNA
- Double-stranded
- Sugar phosphate backbone
- Has complimentary nitrogenous bases
What are the 5 nitrogenous bases?
- Adenine
- Thymine
- Cytosine
- Thymine
- Uracil (in RNA)
What are histones?
Proteins that have DNA wrapped around them
What is the pair of maternal and paternal chromosomes called? (in a somatic cell)
A homologous pair
How many chromosomes are in a somatic cell?
46
Define diploid and haploid
Diploid means the cell has the full amount of chromosomes (46)
Haploid means the cell only has half the amount of normal DNA (23)
What are sex-linked traits?
Traits affected by genes on sex chromosomes
What is the proteome of a cell?
All the proteins that a cell is able to make
Define protein synthesis
The process by which information in the DNA is read and processed to make proteins
What are the 2 stages of protein synthesis?
- Transcription
2. Translation
What are the 3 types of RNA that is transcribed from DNA?
- Messenger RNA (mRNA) : translated in the cytoplasm to make proteins
- Ribosomal RNA (rRNA) : together with ribosomal proteins make up ribosomes
- Transfer RNA (tRNA) : important in binding to amino acids in the cytoplasm
What is post-transitional modification?
The chemical modification of a protein following translation
What are some examples of post-transitional modification?
- Attaching functional groups which that can change or extend it’s function
- Amino acids can be cleaved off the end of a protein
- proteins may be split in half
What are the side chains of an amino acid?
Parts of an amino acid that affect the way protein fold and is shaped
What are some examples of side chains?
- non-polar
- hydrophobic
- hydrophilic
- positively charged
- negatively charged
How many amino acids are in peptides?
2 or more
How many amino acids are in polypeptides?
10 or more
How many amino acids are in proteins?
50 or more
What are the 4 levels of structure of a protein?
- Primary structure
- Secondary structure
- Tertiary structure
- Quaternary
Describe the primary structure of a protein
The sequence of amino acids linked by peptide bonds
Describe the secondary structure of a protein
Proteins fold because the amino acids have different side chains
What are 2 common folding patterns in the secondary structure of a protein?
- Alpha helices (a keratin)
2. Beta pleated sheets (fibroin, silk)
Describe the tertiary structure of a protein
The 3D shape of the protein due to it’s secondary protein (the position of the amino acids)
Describe the quaternary structure of a protein
The combined the 3D structure of two or more polypeptide chains
What are globular proteins?
- polypeptides that are folded into a compact shape
- usually water soluble
- quite mobile
- plays a crucial role in nearly all biological proteins
What are fibrous proteins?
- polypeptides that are in a simple, elongated shape
- insoluble in water
- stable
- provides mechanical support and tensile strength
What are gametes?
Cells that fuse during sexual reproduction (sperm and egg)
What are the 6 stages of mitosis?
- Interphase
- Prophase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis
What is the G1 phase?
The cell produces new proteins, grows and carries out normal tasks for the body.
This phase ends once the cell begins to divide.
What is the S phase?
The DNA molecules in the cell nucleus form exact duplicates of themselves
What is the G2 phase?
Preparation for division
What is the M phase?
The cell divides into 2 daughter cells
What is the G0 phase?
Cells that will stop dividing
What is a nucleotide?
A nitrogenous base plus a deoxyribose plus a phosphate group
