DNA Flashcards

Question

helicase

Answer 1

*H*elicase, breaks *H*ydrogen bonds is the enzyme which unzips the the DNA molecule exposing the nitrogen base code, each exposed strand acts as a pattern or template for the construction of a new DNA molecule

Answer 2

initiated by primase, DNA polymerase works its way along the template strand and add new nucleotides e.g A to T, C to G Nucleotides pair with complementary nucleotide on the existing strand.

Answer 3

makes Primer which consists of nucleotides

Answer 4

Polymerase goes in the direction of 5 prime to 3 prime

Answer 5

DNA ligase seals up the DNA again.

Answer 6

Two new copies of DNA have been made.

Answer 7

Importance: DNA must replicate so that viable daughter cells are formed.

Answer 8

L strands travel from 5 prime to 3 prime, the new strand of the template strand that goes from 5’ to 3’ is the lagging strand, the new strand of the template strand that goes from 3’ to 5’ is the leading strand

Answer 9

- **Body Defense - Antibodies** are specialized proteins made by some white blood cells involved in killing invading microbes(foreign invaders) - **Contractile Proteins** - are responsible for movement. Examples include actin and myosin. These proteins are involved in muscle contraction and movement. - **Enzymes** - are proteins that facilitate chemical reactions. They are often referred to as catalysts because they speed up chemical reactions. - **Hormonal Proteins** - are messenger proteins which help to coordinate certain bodily activities. Examples include insulin, oxytocin. - **Structural Proteins** - are fibrous and stringy and provide support. Examples include collagen, and elastin. Found in connective tissues like ligaments, tendon s and cartilage. - **Transport Proteins** - are carrier proteins which move molecules from one place to another around the body or through cell membranes. Examples include hemoglobin, carrier proteins and channel proteins.

Answer 10

actin/myosin: muscle contraction fibrin: blood clotting amylase: enzyme that breaks down starch haemoglobin: oxygen carrying molecule in red blood cells

Answer 11

location: - DNA: nucleus and mitochondria, RNA: nucleus and cytoplasm strand: - DNA: double strand, RNA: single strand bases: - DNA: thymine + paired, RNA: uracil + single sugar molecule: - DNA: deoxyribose, RNA: ribose

Answer 12

the order of amino acids and therefore the type of protein that is produced.

Answer 13

RiboNucleic Acid

Answer 14

- messenger RNA (mRNA) - ribosomal (rRNA) - transfer RNA (tRNA)

Answer 15

- made in the nucleus - takes the genetic code into the cytoplasm allowing the genetic code to be read by ribosomes

Answer 16

- makes up most the mass of ribosomes, rest is protein - it ensures the correct alignment of mRNA, tRNA and ribosome - has an enzymatic role in the formation of peptide bonds between amino acids

Answer 17

is able to carry a specific amino acid and therefore plays a vital role in protein synthesis

Answer 18

codon is a sequence of three bases in mRNA

Answer 19

1. transcription 2. splicing 3. translation (LATE)

Answer 20

the process by which the genetic instructions are copied (or transcribed) from the DNA to the mRNA molecule.

Answer 21

when triggered by chemical messengers that enter the nucleus from the cytosol and bind to the DNA at the relevant gene

Answer 22

- helicase makes the double stranded DNA come apart, separates about 17 base pairs at a time - RNA polymerase to begin the process of making mRNA, transcribing the bases on one strand of the DNA to make a complementary molecule of mRNA (joins nucleotides with bases that are complementary to those on the DNA template strand) - when there is a cytosine base on the DNA, a guanine will be added to the mRNA - when there is a guanine base on the DNA, a cytosine will be added to the mRNA - when there is a thymine base on the DNA, an adenine will be added to the mRNA - when there is an adenine base on the DNA, a **uracil** will be added to the mRNA - the strand that is copied is called the template strand because it is the template from which the mRNA is made - the other DNA strand is known as the coding strand - because the bases always form complementary pairs, the order of bases on the coding strand will be the same as in the mRNA molecule - mRNA moves into the cytoplasm through a nuclear pore

Answer 23

- Before the mRNA leaves the nucleus the non-coding introns are removed and the coding exons are joined together. - The number of exons joined together and the way they are joined together may not always be the same. - This means that the same piece of DNA can code for different polypeptide chains.

Answer 24

Translation takes place in the ribosomes that are found in the cytoplasm. This is where the messenger RNA is 'interpreted' and the new protein formed.

Answer 25

1. The one end of the mRNA called the start codon attaches to a ribosome. The ribosome "reads" the mRNA. 2. The ribosome decodes the mRNA in groups of three – base triplets or codons – which are complementary to bases in transfer RNA (tRNA). Transfer RNA joins to the mRNA. The sequence of three bases matching the codon is called the anticodon, these determine the amino acid carried by tRNA. 3. The tRNA is specific to an amino acid that it collects and returns to the mRNA. 4. The amino acids are now lined up in order of the instructions (correct sequence) on the mRNA. 5. peptide Bonds form between the amino acids and a polypeptide chain is formed. For each bond formed between the amino acids, the energy from the breakdown of one ATP molecule is required 6. The polypeptide chain folds and becomes a specific shape forming a protein, this is how the protein becomes functional. 7. Once the tRNA has delivered its amino acid, it detaches from the ribosome and can then pick up another amino acid from the cytosol.

Answer 26

pre-mRNA includes introns and exons final mRNA includes only exons

Answer 27

one mRNA molecule may be read by many ribosomes to the same time, producing multiple copies of the protein

Answer 28

no genes carry instructions to code for lipids and carbs synthesis requires enzymes (proteins) genes control the synthesis of lipids and carbs

Answer 29

gene expression is the process of copying information from DNA into mRNA (transcription) and the translating the message into a series of amino acids to form a protein

Answer 30

genes that are not being used to make mRNA are said to be switched off

Answer 31

genes maybe switched on acetyl tags (acetylation) (activate) on the histones or switched off by methyl groups (methylation) (mess up)

Answer 32

histones organise the chromatin that form the chromosome histones prevent strands of DNA becoming tangled histones also affect gene expression

Answer 33

- alters the way DNA filaments are coiled around that histone - enhance or repress gene expression - when cell replicates the histone also replicates

Answer 34

is a form of histone modification that enhances gene expression acetyl tags are on the tail of the histone proteins which allow easier access to DNA regulates gene expression by opening or closing the chromatin structure Acetyl molecules = access = tags on histone = loosely wound gene = turns gene expression on

Answer 35

another histone modification is the amino acids in histones being modified and changing the shape of the amino acid

Answer 36

(not a form of histone modification) these are added to a cytosine in the DNA that are next to guanine (aka CPG sites - Cytosine-Phosphate Guanine) causes DNA to bind more tightly to histones block transcription factors from binding to DNA, by inhibiting the binding of transcription factor(s) to DNA Methyl molecules = mute =tags on DNA (cytosine) =tightly wound gene = turns gene off

Answer 37

RNA polymerase is blocked by methyl molecules that bind directly to the DNA by attaching to the base cytosine. The methyl molecule causes the DNA to tightly wind around its histones. The gene is considered turned off.

Answer 38

Acetyl molecules bind to histones . The addition of these molecules cause the histones to distance themselves from one another. Access is easier when acetyl molecules cause the DNA to be wound more loosely around the histone The gene is considered turned on.

Answer 39

A persons genome is the hereditary information that is encoded in the DNA.

Answer 40

Their epigenome is the sum of all the factors that determine when, where and which genes are switched on or expressed. The epigenome helps to control which genes are active in a particular cell and the fire which proteins will be produced. If the epigenome is abnormal, certain cells may be abnormal and it will result in diseases.

Answer 41

(the study of) changes in gene expression that result from the mechanisms other than changes in the genes that is in the DNA or the genome

Answer 42

- diet e.g high in fats - stress - exposure to pollutants (smoking, chemicals) - alcohol

Answer 43

epigenetic and environmental differences

Answer 44

Age - more experience, more exposure to the environment, they have differing DNA as their epigenome is different and less similar.

DNA Flashcards

(68 cards)