Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Human Biology > DNA, Protein Synthesis and Epigenetics (Chapter 9) > Flashcards

DNA, Protein Synthesis and Epigenetics (Chapter 9) Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Structure of DNA

A

-Deoxyribonucleic acid is a double stranded helix
- It consists of repeating nucleotides
- Each nucleotide contains a deoxyribose sugar, a phosphate group, and 1 of 4 nitrogenous bases
- The DNA strands are connected by weak hydrogen bonds between base pairs
- Adenine always pairs with Thymine and Cytosine always pairs with Guanine
- The DNA strands run in opposite directions with one going from 3’ to 5’ and the other going from 5’ to 3’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Full name for DNA

A

Deoxyribonucleic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A nucleotide consists of

A

One phosphate, one deoxyribose sugar, one nitrogen base either Adenine, Thymine, Guanine, Cytosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The two base pairs and number of hydrogen bonds

A
  • A pairs with T and is joined by 2 hydrogen bonds
  • G pairs with C and is joined by 3 hydrogen bonds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Chromatin

A

Coiled strands of DNA. For gene transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Chromosomes

A

Super coiled or condensed strands of DNA. For cell division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Histone

A

A protein that DNA wraps around in order to be packaged into the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Nucleosomes

A

Groups of histones packaged together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Gene

A

A section of DNA that codes for a protein. Each protein molecule has one gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is a gene coded?

A

By the sequence of nucleotides contained within it. Differences in this sequence of nucleotides provides variation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Alleles

A

Variations of a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many base pairs in a gene

A

Up to 1000, providing huge potential for variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Mitochondrial DNA

A

Inherited from the mother through the egg cell. They are small circular strands of DNA, which are not bound to histone proteins. It contains 37 genes which are all essential for mitochondria to function .Around 5-10 in each mitochondria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the difference between DNA and RNA

A
  • DNA contains a deoxyribose sugar, RNA contains a ribose sugar
    -DNA is double-stranded, RNA is single-stranded
    -DNA is found in the nucleus, RNA is found in the nucleus and the cytoplasm
    -DNA contains thymine, RNA contains uracil
    -DNA contains genes, RNA transfers genetic code
    -DNA is synthesised from itself, RNA is synthesised from DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

DNA Replication

A

The process of duplicating DNA into two exact replicas, usually before a cell divides to ensure an even amount in each new daughter cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Helicase

A

An enzyme that breaks the hydrogen bonds between nitrogen bases to create two single strands of DNA

17
Q

Polymerase

A

An enzyme that helps free nucleotides in the nucleus to attach themselves to their complementary base partners.

18
Q

Genome

A

An organism’s complete set of genetic information.

19
Q

Synthesis

A

The process of combining smaller molecule to make larger molecules

20
Q

DNA role in protein synthesis

A

DNA acts as a template that codes for the correct order in which amino acids are to be joined to the chain to make a protein

21
Q

Two stages of protein synthesis

A
  • Transcription in the nucleus
  • Translation at ribosomes in the cytoplasm
22
Q

Transcription definition

A

The process by which the genetic instructions are copied from the DNA to the mRNA molecule.

23
Q

Translation definition

A

The production of a protein using the information that is coded in the mRNA molecule.

24
Q

Transcription steps

A
  • DNA molecules are too large to leave the nucleus, so the genetic code must be copied in messenger RNA (mRNA), which is small enough to pass through the nuclear pores of the nucleus
  • to form the mRNA molecule the DNA is first unzipped by the helicase enzyme
  • Then RNA Polymerase reads the template DNA strand from 3’ to 5’ and builds a single strand of mRNA that runs from 5’ to 3’ and is complementary to the template strand
  • At the end of the gene there will be a section of bases that tell the RNA polymerase to stop coding (known as a stop codon)
  • The non template strand, called the coding strand is not used in the process
  • Before the mRNA can leave the nucleus, it must undergo splicing where the non-coding regions of the DNA strand called introns are removed from the strand
  • This produces a strand that consists of just coding regions called exons
  • These leftover exons are joined together by ligase
  • The mRNA can then migrate out of the nucleus through the nuclear pores of the ribosomes
25
Q

Translation steps

A
  • In the cytosol, a ribosome attaches to one end of the mRNA molecule at a particular sequence of bases called the start codon (AUG)
  • This ensures that the ribosome attaches to the correct end of the mRNA
  • The ribosome reads the mRNA sequence in groups of 3 known as codons, which correspond to a specific amino acid
  • Small molecules of RNA called transfer RNA (tRNA) bring the corresponding amino acid to the codon. One end of the tRNA binds to it’s corresponding amino acid, while the other end has a loop with 3 nitrogenous bases called an anticodon that is complementary to a specific codon.
  • the amino acids are joined together by peptide bonds to form the protein chain
  • Once each tRNA molecule delivers its amino acid, it detaches from the ribosome and can then pick up another amino acid from the cytoplasm
  • Eventually a stop codon will come up, stopping translation and releasing the complete protein from the ribosome. The stop codons are UAA, UAG, UGA
26
Q

gene expression

A

The process of copying information from DNA on to mRNA and then translating the message into a series of amino acids to form a protein.

27
Q

Epigenetics definition

A

Changes in gene expression that result from environmental mechanisms other than changes in DNA sequence

28
Q

Epigenome

A

Consists of the histones and other chemicals around the DNA sequence. It allows the body to control which genes to express at what time.

29
Q

How can genes be regulated epigenetically?

A

Through changes in the chromatin

30
Q

Histone acetylation

A

Where an acetyl group (CH3CO) is added to a histone protein, encouraging increased expression.

31
Q

DNA Methylation

A

Adding a methyl group (CH3), which encourages decreased expression

32
Q

Explain DNA Methylation

A
  • Methyl group can only be added between a cytosine and guanine molecule
  • the methyl group acts as a marker that means the DNA polymerase can’t bind to DNA for transcription
  • Genes are basically switched off in this state
  • Methylation increases with time as we become more and more exposed to varying environemtnal factors as we age
  • some of the these methyl group markers can become imprinted and can then be passed onto offspring
33
Q

Monozygotic twins

A

When identical twins develop from a single zygote, which for some reason divides and becomes 2 individuals

34
Q

Dizygotic twins

A

where 2 eggs are fertiled by 2 sperm at the same time and do not have identical genetic code

Human Biology (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions