Cell Structure Flashcards

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1
Q

What is a nucleus

A

Large organelle surrounded by a nuclear envelope which contains pores. The nucleus contains chromatin.

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2
Q

What is the nucleolus

A

Synthesised ribosomes and ribosomal RNA

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3
Q

What is a lysosome

A

A round organelle surrouned by a membrane with no clear internal structure. Contains digestive enzymes

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4
Q

What is ribosomes

A

Small organelle that floats free in the cytoplasm or is attached to the rough endoplasmic reticulum. Made up of proteins and RNA. No membrane. Protein synthesis.

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5
Q

What is rough endoplasmic reticulum

A

A system of membrane bound flattened sacs. The surface is covered with ribosomes. Protein enter the rer and are folded and processed. Transported to the golgi apparatus in vesicles.

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6
Q

What is the soft endoplasmic reticulum

A

A system of membrane bound flattened sacs but no ribosomes. Lipid synthesis

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7
Q

What is golgi

A

A group of fluid filled membrane bound flattened sacs. Formed by fusion of vesicles from the endoplasmic reticulum. Proteins from RER fuse to form flattened sacs of the golgi and the golgi further processes. Proteins enter more vesicle (lysosome) and contain digestive enzymes.

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8
Q

What is mitochondria

A

Has a double membrane- inner is folded to form a structure called cristae. Inside has matrix which contains enzymes. Inner membrane and cristae have proteins embedded that are involved in the regeneration of ATP during aerobic respiration.

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9
Q

What are Centrioles

A

Small Hallow cylinders made of microtubules that produce spindle fibres during cell division

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10
Q

What is chitin

A

Component of cell walls in fungi

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11
Q

What is cellulose

A

Component of cell walls in plants

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12
Q

What is in the inner membrane of the chloroplast

A

Have a thylakoid membrane. The flatten discs are thylakoids. Stacks are called grana

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13
Q

Organelles in prokaryotes

A

Capsule- prevent dedication, protects cells from antibiotics.
Ribosomes- smaller than eukaryotic
DNA- in a single circular loop no associated with proteins
Plasmid- small loops of DNA which can be shared between cells usually contain useful genes
Cell wall- made of murien- polysaccharide and peptide mix
Flagellum- used for locomotion
Membrane infold- increasedsurface area for respiration or photosynthesis.

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14
Q

Binary fission of prokaryotes

A
  1. DNA and plasmids replicate. Plasmids can be replicated many times.
  2. Cell elongates and DNA moves to opposite poles of cell.
  3. Cytoplasm begins to divide and new cell walls begin to form.
  4. The cytoplasm divides to produce to daughter cells. Each contain an identical DNA loop but can contain a different number of plasmid copies.
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15
Q

What are fungi

A

They are eukaryotic- they are similar to plant cells except they contain no chloroplasts and their cell walls are made of chitin not cellulose.

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16
Q

What is a virus

A

. Viruses are neither prokaryotic nor eukaryotic
. They are acellular non-living particles
. They are 1000x smaller than bacteria
. They consist of a genetic material that are protected by a protein coat called the capsid. Enclosed in a lipid envelope.

17
Q

What is virus replication

A
  1. Virus detects host cell by recognising protein marker on its membrane. Virus attaches to cell using attachment proteins
  2. Virus injects genetic material into cell
  3. Cell reproduces the genetic material and reads it creating new viral proteins
  4. Virus leave cell using some of the cells own membrane to form itself
18
Q

Transmission electron mircoscope

A

. It works by shooting a beam of electrons at a thin slice of a sample and detecting those electrons that make it through to the other side
. The TEM lets us look in very high resolution at a thin section of a sample
. This makes it particularly good for learning but how components inside a cell are structured internally

19
Q

Scanning electron microscope

A

. Uses a focused beam of high-energy electrons which reflect off the surface of structures
. Gives a 3D image, samples do not have to be thin/cross sections

20
Q

Equation to work out magnification

A

Image size= actual size x magnification

21
Q

TEM

A

. shooting beams of electrons at a thin slice of a sample and etectjng those electrons that make it through to the other side.
. The TEM let us look in very high resolution at a thin section of a sample.
. This makes it particularly good for learning about how components inside a cell.

22
Q

SEM

A

. Uses a focused beam of high-energy electrons which reflect off the surface of structures
. Gives a 3D image, sample do not have to be thin/cross sections

23
Q

3 stages of ultracentrifugation

A

. Homogenisation
. Filtration
. Ultracentrifugation

24
Q

What solution must the tissue be in

A

Cold isotonic buffered solution

25
Q

Why must solution be cold

A

Reduces enzyme activity which may break down organelles

26
Q

Why must the solution be isotonic

A

Prevents organelles from bursting or shrinking due to osmotic water gain or loss

27
Q

Why must the solution be buffered

A

The maintain a constant pH

28
Q

First step of cell fractionation

A

Homogenising- breaks up the tissue to open the cell membrane

29
Q

Second step of cell fractionation

A

Filtration to remove large debris that cound sink to the bottom of the tube

30
Q

Last step of cell fractionation

A

Centrifuging the faster the spinning the greater the force. Each time the supernatant is respun at a higher speed to get smaller organelles.

31
Q

What is mitosis

A

Genetically identical daughter cells.

32
Q

Stages of mitosis

A

Prophase- chromosomes condense. Nuclear envelop breaks down. Centrioles go to opposite poles of the cells.
Metaphase- line up along the centre of the cell. Spindle fibres attach to the centromeres.
Anaphase- spindle fibres contract to pull chromatids to opposite poles of the cell
Telophase- the chromosome uncoils. Nuclear envelope reforms. Spindle fibres and centrioles break down

33
Q

What is cytokinesis

A

Concludes telophase as the cytoplasm is separated. Formation of a cleavage. Thin cell wall material

34
Q

What is interphase

A

Where the chromosomes disassociate from the chromatin, the spindle fibres disintegrate and the nucleolus form. Chromosomes will replicate ready for mitosis again

35
Q

What does cytokinesis do to the mass

A

Cell mass will increase until cytokinesis resets the mass.

36
Q

What is cancer

A

Cancer is uncontrolled cell division. Often caused by mutations in genes.

37
Q

Calculation for mitotic index

A

Mitotic cells/total cells X 100

38
Q

Howndoesncancer treatment work

A

By inhibition of DNA replication or by inhibition of spindle fibres

39
Q

What cells are vulnerable to being targeted by cancer treatment

A

Follicle dermal cells and epithelial villi cells