DNA: the code of life Flashcards Preview

LS12 - Life Sciences > DNA: the code of life > Flashcards

Flashcards in DNA: the code of life Deck (40)
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1
Q

Full name of DNA

A

Deoxyribonucleic acid

2
Q

Organisms with no nucleus

A

prokaryotes e.g. bacteria

3
Q

Location of DNA in eukaryotes

A

Nucleus

Also in:

  • Mitochondria in plants and animals
  • Chloroplasts in plants
4
Q

Examples of eukaryotic kingdoms

A
  • plants
  • animals
  • fungi
  • protists
5
Q

DNA and proteins forming a dense network of fibres in the nucleus

A

Chromatin

6
Q

Parts of the nucleus include

A
  • Double nuclear membrane
  • Nucleoplasm
  • Chromatin/DNA and proteins
  • Nucleolus
7
Q

Phase of a cells cycle when the chromatin condenses into distinct chromasomes

A

Prophase of Mitosis and Meiosis

8
Q

How do you make a karyotype & what do we use it for?

A
  • Cut out images of a cells chromosomes
  • Arranged in pairs and numbered in order of size
  • Shows chromosomal content of cells
  • Can be used to diagnose chromosome level genetic disorders
9
Q

Number of chromosomes in humans

A

46 chromosomes (23 pairs)

10
Q

Sex chromosomes for a female and a male

A
  • XX = females
  • XY = males
11
Q

A gene is?

A
  • A specific portion of DNA
  • with a specific sequence
  • that determines a particular characteristic of an organism.
12
Q

What exactly do genes code for?

A

Protein molecules

13
Q

DNA not containing genes

A

non-coding DNA

14
Q

Extra-nuclear DNA often referred to as mtDNA and cpDNA

A

mitochondrial DNA and chloroplast DNA

15
Q

Reason for adding salt in a DNA extraction

A

To condense DNA and proteins after cells have burst

16
Q

Reason for adding detergent in a DNA extraction

A

To remove membrane lipids

17
Q

Reason for adding protease (e.g. meat tenderiser) in a DNA extraction

A

To remove proteins from membranes and chromatin

18
Q

Reason for adding ice cold alcohol in a DNA extraction

A

To purify the DNA as DNA forms a solid precipitate in the alcohol

19
Q

Initially credited with identifying the double helix structure of DNA

A
  • James Watson
  • Francis Crick
  • (in 1953)
20
Q

Performed the X-ray diffraction and photographed it to help discover the structure of DNA

A
  • Rosalind Franklin
  • Maurice Wilkins
21
Q

Repeating units making up DNA are called…

A

Nucleotides

22
Q

Composition of one nucleotide

A
  • Phosphate
  • Deoxyribose
  • Nitrogenous base
23
Q

The five different nitrogenous bases

A
  • A-Adenine
  • T-Thymine
  • C-Cytosine
  • G-Guanine
  • U-Uracil
24
Q

Purine bases

A
  • Adenine
  • Guanine
25
Q

Pyrimidine bases

A
  • Thymine
  • Cytosine
26
Q

Nitrogenous base pairing (complementary bases)

A
  • A-T (or A-U in RNA)
  • C-G
27
Q

Type of bond between complementary bases

A

Hydrogen bonds

28
Q

What are polymers?

A

Compounds made with repeating units (e.g. DNA)

29
Q

The method Watson and Crick employed to discover the structure of DNA

A

Built a model using already known facts about DNA’s composition and structure

30
Q

The role of DNA

A
  • Carry all the genetic code for an organism
  • DNA code is needed for protein synthesis
  • Replication provides genetic code for both daughter cells in cell division
  • Passing hereditary information from parents to offspring
31
Q

Phases of the cell cycle

A
  • Interphase, made up of:
  • First gap phase (G1) - growth in physical size
  • Synthesis phase (S) - DNA replication
  • Second gap phase (G2) - checking the cell is ready to divide, and
  • Mitosis
32
Q

Phase of cell cycle when DNA replication takes place

A

Interphase - Synthesis phase (S)

33
Q

Errors in DNA code copying during DNA replication that become permanent changes

A

Mutations

34
Q

Sequence of steps in DNA replication

A
  • DNA unwinds to form a ladder
  • Enzymes unwind and unzip DNA, breaking hydrogen bonds
  • Template exposed
  • Free floating nucleotides in nucleoplasm
  • Enzymes control joining of free nucleotides to existing template
  • Forming complimentary strands
  • Two DNA strands reform
35
Q

Identifying someone using their DNA is called

A

DNA profiling

36
Q

Main steps in the process of electrophoresis

A
  • DNA loaded into a gel
  • Electric current makes DNA migrate towards positive electrode
  • Smaller fragments of DNA move faster
  • A banding pattern is photographed under ultraviolet light
37
Q

Process of DNA profiling

A
  • DNA from cells is isolated
  • Enzymes cut DNA at very specific sites into different lengths (different for each individual)
  • DNA fragments are amplified (copied) by PCR
  • Electrophoresis is used to identify the DNA profile
  • Banding patterns are compared to known DNA samples
38
Q

Arguments for use of DNA profiling

A
  • Solve crimes
  • Determine paternity
  • Find missing persons
  • Identify people/ remains
39
Q

Arguments against use of DNA profiling

A
  • Invasion of privacy for victim and suspect
  • Possibility of tampering evidence
  • Misuse of technology
40
Q

Give the complementary DNA sequence for: ACTTCTA

A

TGAAGAT