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Bio > Cell Division+Immunology+transport Across Membranes > Flashcards

Cell Division+Immunology+transport Across Membranes Flashcards

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Biology 101 flashcards
1
Q

Describe the appearance and behaviour of chromosomes during MITOSIS

A

(During prophase)
Chromosomes coil/condense/shorten and become visible
Appear as identical sister chromatids joined at the centromere

(Metaphase)
Chromosomes line up on the equator
Chromosomes attached to spindle fibres
By their centromere

(Anaphase)
Centromere splits
Spindle fibres contract
Sister chromatids move to opposite piles of the cell making v shape
(Telophase)
Chromosomes uncoil and unwind // cytokinesis also happens

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2
Q

Describe and explain the processes that occur during meiosis that increase genetic variation

A

Homologus chromosomes pair up
Independent segregation
Maternal and paternal chromosomes pair up and reshuffled in random combination
Crossing over leads to exchange of non sister chromatids between homologous chromosomes
Both create new combination of alleles

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3
Q

In which part of the cell cycle does dna replication take place

A

S-phase

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4
Q

Describe the role of spindles during mitosis

A

Attachment of chromatids at centromere, separation of chromatids

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5
Q

Importance of meiosis

A

Halves chromosome number
Diploid

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6
Q

Describe the role of centromere in mitosis

A

Holds chromatids together
Attaches to spindle
Allows chromatids to be separated

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7
Q

Odd number of chromosomes cannot produce fertile gametes as the chromosomes cannot pair

A
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8
Q

To tell if cell undergoing mitosis in a picture

A

Chromsomes will be visible because they have condensed
Chromosome made up of 2 chromatids because dna replicated

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9
Q

Suggest one advantage to a bacterium of secreting an extracellular

A

To digest proteins
So they can absorb amino acids for growth

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10
Q

Processes that take place during G1 of the cell cycle are

A

• cell growth
• protein synthesis
• production of Rna
• production of organelles

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11
Q

Reasons why a cell might not pass through G1 is

A

• Cell is not big enough
• Dna has been damaged
• Cell has not produced enough proteins/organelles
• environment does not contain enough nutrients

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12
Q

Describe binary fission in bacteria

A

1) Replication of circular DNA
2) Replication of plasmids
3) Division of cytoplasm to produce daughter cells

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13
Q

Differences between mitosis and meiosis

A

• Mitosis is 1 division, WHEREAS meiosis is 2 divisions
• In mitosis, daughter cells are genetically identical, WHEREAS in meiosis, daughter cells are genetically different
• In mitosis, 2 daughter cells are produced WHEREAS in meiosis, 4 cells produced
• In mitosis, diploid to diploid/haploid to haploid WHEREAS in meiosis diploid to haploid
Separation of homologous chromosomes only happens in meiosis
Independent segregation and crossing over only occur in meiosis

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14
Q

Explain how the chromosome number is halved during meiosis

A
  1. Homologous chromosomes (pair);
  2. One of each (pair) goes to each (daughter)
    cell / to opposite poles;
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15
Q

Describe process of crossing over and explain how it increases genetic diversity

A

-homologous pairs of chromosomes form a bivalent
-chiasma form
-equal lengths of non-sister chromatids between homologous chromosomes are exchanged
-producing new combinations of alleles

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16
Q

Describe the features of prophase

A

Nuclear membrane begins to breakdown;
Centrioles move to poles of the cell;
Chromosome condense;

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17
Q

Describe the features of metaphase

A

spindle fibres form
spindle fibres attach
to the centromere of chromosomes
chromosomes align at the equator

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18
Q

Describe the features of Anaphase

A

Spindle fibres shorten;
Centromere splits;
Sister chromatids are separated;
Pulled to opposite poles of the cell;

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19
Q

Describe the features of telophase

A

Nuclear membrane begins to reform;
Chromosomes unwind

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20
Q

Describe the role of the spindle during mitosis

A

Attachment of centromeres/chromosomes/chromatids; Separation of centromeres/chromatids/chromosomes;

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21
Q

Importance of meiosis

A

Halves chromosome number
Increases variation within a population

22
Q

Role of centromere during mitosis

A

Holds chromatids together
Attaches to spindle fibre
Allowing chromatids to be separated during anaphase

23
Q

Antigen

A

Foreign protein
That stimulates an immune response leading to the production of an antibody

24
Q

Antibody

A

Protein
Produced by plasma cells
In response to an antigen in an immune response

25
Q

To check for Aids

A

Look for AIDS-related symptoms
Check number of thelper cells

26
Q

Children receive HIV antibodies from their mum so
Test will always be positive

A
27
Q

Elisa teat may contain a control well to see that only enzyme is causing a colour change and to see washing is effective

A
28
Q

Give 2 ways pathogens can cause disease

A

• Release toxins which can directly damage tissue
• can replicate and inside and destroy host cells

29
Q

How do antibodies assist in the destruction of pathogens

A

• AGGLUTINATION- specific antibodies bind to the antigen and clump them together

• Opsonisation- Marking pathogens so phagocytes recognise and destroy pathogens more efficiently
• prevent pathogen replication

30
Q

If a virus is inactive

A

• The cells arent being produced (link to the question- which cells have they talked about
• Because virus is not replicating

31
Q

Advantage of programmed cell death

A

Prevents replication of virus

32
Q

What is a monoclonal antibody

A

Antibodies produced from the same B or plasma cell
Or antibodies with the same tertiary structure

33
Q

Give 2 cells other than pathogens that can cause disease

A

• Cancer cells
• Cells from other organisms

34
Q

What is the role of the disulfide bridge in forming the quaternary structure of an antibody?

A

Joins two different polypeptides together

35
Q

Explain why these antibodies are only effective against a specific pathogen. (2)

A

Antibodies have a specific tertiary structure;
Antigens are complementary to antibody

36
Q

When a vaccine is given to a person, it leads to the production of antibodies against a disease-causing organism. Describe how.

A
  1. Vaccine contains antigen from pathogen;
  2. Macrophage presents antigen on its surface;
  3. T cell with complementary receptor protein
    binds to antigen;
  4. T cell stimulates B cell;
  5. (With) complementary antibody on its surface;
  6. B cell secretes large amounts of antibody;
  7. B cell divides to form clone all
    secreting/producing same antibody;
37
Q

Describe the difference between active and passive immunity.

A
  1. Active involves memory cells, passive does not;
  2. Active involves production of antibody by plasma cells / memory cells;
  3. Passive involves antibody introduced into body from outside / named source;
  4. Active long term, because antibody produced in response to antigen;
  5. Passive short term, because antibody (given) is broken down;
  6. Active (can) take time to develop / work, passive fast acting;
38
Q

Tests using monoclonal antibodies are specific. Use your knowledge of protein structure to explain why. (3)

A

Specific primary structure;
Specific tertiary structure;
So only complementary to one antigen

39
Q

Describe the structure of HIV

A

• RNA as genetic material
• reverse transcriptase
• protein capsid
• viral envelope
• attachment proteins

40
Q

Deacribe how presentation of a virus antigen leads to the secretion of an antibody against this virus antigen

A

Th Cell binds to the antigen on the APC
• This TH cell stimulates a specific B cell by the release of cytokines
• B cell divides by mitosis
• Forming plasma cells that release antibodies

41
Q

Describe and explain the role of antibodies in stimulating phagocytosis

A

Bind to antigen and act as markers
Antibodies cause agglutination and attract phagocytes

42
Q

Describe how HIV is replicated

A
  1. Attachment proteins attach to receptors on helper T cell/lymphocyte;
  2. Nucleic acid/RNA enters cell;
  3. Reverse transcriptase converts RNA to DNA;
  4. Viral protein/capsid/enzymes produced;
  5. Virus (particles) assembled and released (from cell);
43
Q

What can change in chromosome number be cause by

A

Change in chromosome number can be caused in meiosis
Homologous chromosomes fail to separate

44
Q

Phagocytosis

A

Phagocyte engulfs pathogen
Pathogen enters the cytoplasm of the phagocyte in a vesicle called phagosome
Lysosomes fuse with vesicle releasing hydrolytic digestive enzymes
Which hydrolyse pathogen
Antigen presented on its cell surface membrane

45
Q

Outline roles of organelles in production+transport+release of proteins in eukaryotic cells

A

Dna in nucleus codes for proteins

Ribosomes produce protein

Mitochondria produce ATP for protein synthesis

Golgi body package and modify

Vesicle/RER transports (remember RER
can since its transporting proteins)

46
Q

Give example of using monoclonal antibodies in medical treatment

A

Targets drugs
Block antigens

47
Q

Type of a white blood cell

A

Phagocyte

48
Q

Interphase
Where is majority of a life of a cell spent

A

Period between divisions

Interphase G1

49
Q

Where is genetic info carried in

A

Genes

50
Q

How do mitochondria + chloroplast replicate

A

Binary fission

51
Q

Genetic variation increases by

A

Crossing over
Random fertilisation of gametes
Mutatins

52
Q

When does crossing over occur

A

During prophase+metaphase in 1st division

Bio (8 decks)

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