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A Level Biology - Seneca Topic Flashcards > Topic 6 > Flashcards

Topic 6 Flashcards

1
Q

Indicating the Time of Death

A
  • Can be used to tell how long someones been dead for

- Depends on situation eg in water = harder to tell

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2
Q

Extent of Decomposition

A
  • First Couple Hours - first hours of death/upto couple days

- Rate increases if temperature is higher and more oxygen available

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3
Q

Why are Microorganisms involved in decomposition

A
  • Work to break down Organic Matter by secreting enzymes

- Carbon Compounds are recycled

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4
Q

Body Temperature during Death

A
  • Alive, heat = metabolic reactions
  • Cools 2 degrees every hour after death
  • Factors affect this such as clothing
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5
Q

Forensic Entomology

A

-Finding out type of insects/microorganisms on body

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6
Q

Stages of Succession after Death

A

-Type of bacteria indicates period of death

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7
Q

Degree of Muscle Contraction after Death

A
  • Rigor Mortis - stiffening of muscles
  • muscles need ATP - attach the myosin head from the actin after contraction
  • Anaerobic Respiration, lactic acid, glucose used up
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8
Q

Common Features in Euk and Pro Cells

A
  • Plasma Membrane
  • Cytoplasm
  • DNA
  • Ribosomes
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9
Q

DNA in Prokaryotes (Non-Living)

A
  • Circular molecule in Cytoplasm
  • Some smaller loops = Plasmids
  • Bacteria - Plasmid Exchange
  • eg Immunity Spread
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10
Q

Capsule Function

A

-Enable Prokaryotes to attach surfaces

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11
Q

Flagella Function

A

-tail like used for locomotion - in some pro.

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12
Q

Pili Function

A

-used to exchange genetic material during conjugation (type of reproduction)

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13
Q

Fimbriae Function

A

Used to attach host cell

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14
Q

Virus Structure

A
  • nucleic acids
  • Surrounded by protein called capsid
  • Smaller then bacteria
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15
Q

What is DNA Profiling and when is it used

A
  • Technique used for analysing samples of DNA
  • Specific DNA patterns used to identify people, family, diseases etc
  • Can be used in Crime Scenes
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16
Q

How do Scientists do DNA Profiling

A

-Order up all the Nucleotides, then compare to the existing DNA

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17
Q

Polymorphisms?

A
  • Part of genomes that vary greatly

- used to distinguish between individuals and groups

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18
Q

Why is Polymerase Chain Reaction Used

A

-Increase DNA sample size

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19
Q

Polymerase Chain Reaction Steps (PCR)

A
  • DNA heated to 96C = denatured strands to make them single
  • Cooled to 60C to allow primers to anneal strands of DNA
  • Heated to 72C so Taq Polymerase can work at optimum conditions = Extends nucleotide chains
  • Repeated 25-35 times
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20
Q

What is a Primer

A

short lengths of DNA which free nucleotides can attach too

21
Q

Why is Gel Electropheresis used?

A

-Separates DNA fragments according to size (number of base pairs)

22
Q

Gel Electropheresis Steps

A
  • DNA loaded into wells full of agarose gel
  • Electric current passed through
  • Negative charged DNA moves through to + electrode
  • Smaller fragments move faster
  • DNA ends up arranged in bands - similar strands together
23
Q

Examples of Obtained DNA

A

-Hair, Skin, Saliva (Contains body cells)

24
Q

How is DNA extracted from cells

A
  • Nucleus extraced and isolated from cellular matter

- Using Detegents

25
Q

Taq Polymerase

A
  • DNA polymerase which attaches nucleotides to a single strand of DNA.
  • Optimum Temperature is 72C
26
Q

3 reasons why DNA application (Profiling) is used

A
  • check relatedness of people
  • risk of genetic disease
  • identify potential criminals
27
Q

What does HIV inhibit

A

-The immune System

28
Q

Structure of HIV (4 bits)

A
  • Capsule
  • RNA
  • Enzymes (reverse transcriptase/integrase)
  • Viral Envelope
29
Q

Capsule in HIV role

A
  • Inside the centre of HIV

- Contains Genetic Material and Enzymes

30
Q

RNA in HIV role

A
  • Two strands of RNA

- Inside capsule

31
Q

Enzymes in HIV role

A
  • Reverse Transcriptase and Integrase

- Help with infection

32
Q

Viral Envelope in HIV role

A
  • Capsid enclosed by this
  • Glycoproteins on surface
  • Bind to surfaces of T helper cells to infect cells
33
Q

HIV Replication 6 steps

A

1) Bind to T Helper Cells
2) Release of Capsid
3) Reverse Transcriptase
4) Integrase
5) Expression
6) Release of HIV

34
Q

HIV Replication step 1 - Bind to T Helper Cells

A

-HIV is binded to t Helper cells via glycoproteins

35
Q

HIV Replication step 2 - Release of Capsid

A
  • Capsid injected into T Helper Cells

- Enzymes RT and I are released into cell

36
Q

HIV Replication step 3 - Reverse Transcriptase

A
  • Converts single stranded RNA from HIV into Double stranded DNA
  • Moves into the Nucleus
37
Q

HIV Replication step 4 - Integrase

A

-Inserts HIV DNA into T helper cells

38
Q

HIV Replication step 5 - Expression

A
  • Genes of HIV DNA are expressed in T helper Cells
  • HIV Proteins synthesised
  • new HIV RNA is made
39
Q

HIV Replication step 6 - Release of HIV

A
  • New HIV viruses released by T helper Cells
  • T Helper cells die
  • More cells infected
40
Q

What is Aids

A

-Caused by HIV infection

41
Q

Cause of Aids

A
  • When T helper cells die - more infected cells
  • Immune system weakened
  • Makes it highly susceptible to infection by other pathogens (Aids)
42
Q

Symptoms of Aids

A
  • Flu (chills and fever) - 4 weeks of infection
  • More vulnerable to infections
  • Can take upto 10 years to develop
43
Q

What is TB?

A

-caused by Myobacterium Tuberculosis, bacteria effects the lungs

44
Q

How is TB spread?

A
  • spread by air droplets

- person breathes in or sneezes

45
Q

How does the immune system try and prevent TB

A
  • Phagocytosed by Macrophages
  • DOESNT kill bacteria
  • Bacteira lies dormant in macrophage
46
Q

How is TB activated

A
  • when immune system is weakened

- gives bacteria time to reactivate and infect them with TB

47
Q

Symptoms of TB

A
  • Persistent and Violent coughs

- Night sweats

48
Q

How can TB be treated

A

-course of antibiotics

49
Q

Sequence of Events for TB infection

A

1) Person breathes in droplets
2) bacteria enters lungs
3) Bacteria phagocytosed by macrophage
4) M.Tuber lies dormant in Macrophage
5) Person immune system weakens, Bac activates causing TB

A Level Biology - Seneca Topic Flashcards (8 decks)

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