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biology > 12.5 - Studying cells > Flashcards

12.5 - Studying cells Flashcards

1
Q

EUKARYOTIC CELLS

1) The DNA in eukaryotic cells is…
2) So animal cells are eukaryotic because they have a…
3) These cells also have membrane bound…

A

1) enclosed by a nuclear membrane
2) nucleus
3) organelles

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2
Q

NUCLEUS

What is the structure of a nucleus, it has:
1) A nuclear.. / double.. and nuclear..
2) Chromo… and chroma…
3) a nucleo..

What are the functions of the nucleus?
4) Stores genetic…
5) Site of DNA…
6) Site of production of… (3)

A

1) A nuclear envelope / double membrane and nuclear pores
2) Chromosomes and chromatin (DNA associated with histones)
3) a nucleolus

4) Stores genetic information for polypeptide production
5) replication
6) mRNA, tRNA + rRNA (nucleolus)

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3
Q

MITOCHONDRIA

What is the structure of a mitochondrion, it has:
1) A double…
2) An inner… that is highly… to form
3) A ma… (liquid part) containing…

What are the functions of a mitochondrion?
4) It is the site of…
5) Cells that need a lot of ATP have a lot of… e.g.
6) It also has DNA to code for… needed in…

A

1) membrane
2) membrane that is highly folded to form cristae (that increase SA)
3) Matrix - containing mitochondrial DNA (circular), 70S ribosomes, proteins + lipids

4) ATP production by aerobic respiration
5) mitochondria, e.g. muscle cells (for muscle contraction) + epithelial cells (for active transport of ions)
6) enzymes needed in respiration

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4
Q

ROUGH ENDOPLASMIC RETICULUM

What is the structure of the RER?
1) It has highly folded membranes called:
2) That are embedded with…
3) It is joined to the…

Function?
4) It is the site for…

A

1) cisternae
2) (80S) ribosomes
3) nucleus

4) protein synthesis

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5
Q

SMOOTH ENDOPLASMIC RETICULUM

What is the structure?
1) Like the RER, it has highly folded membranes called:

What is the function?
2) It is the site for:

A

1) cisternae

2) lipid synthesis - recombines glycerol and fatty acids into triglycerides AND:
the storage of lipids.

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6
Q

RIBOSOMES

Structure
1) It is made up of two…
2) That are made of… and…
3) A eukaryotic cell contains…

Function
4) It is the site of…

A

1) subunits (large and small)
2) long strands of rRNA and (ribosomal) proteins.
3) 80S ribosomes

4) Protein synthesis

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7
Q

GOLGI APPARATUS/BODY

Structure
1) It is made up of…
2) It also has Golgi…

Function
3) It sorts, modifies and packages…

A

1) flattened sacs made of membrane filled with fluid
2) vesicles that pinch off from the main membrane

3) proteins and lipids (that contain proteins) into vesicles

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8
Q

LYSOSOMES

Structure
1) It is a membrane-bound organelle that stores and releases many…

Function
2) The hydrolytic enzymes are used to…
3) —– are types of —– that contain many lysosomes, as they hydrolyse invading pathogens

A

1) hydrolytic (digestive) enzymes

2) digest damaged + worn out organelles for reuse of materials
3) phagocytes are types of white blood cells

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9
Q

CELL SURFACE MEMBRANE

Structure
1) Made up of..p..specific transport p…and c… arranged into a f…

Function
2) Controls the passage of…

A

1) phospholipids, specific transport proteins, carbohydrates - fluid mosaic model

2) molecules in and out of the cell

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10
Q

CENTRIOLES

Structure
1) Mi…

Function
2) They form a network of…. onto which chromosomes….
3) They pull….apart during..

THEY ARE NOT FOUND IN….

A

1) Microtubules

2) spindle fibres - attach
3) chromosomes / chromatids apart during mitosis

NOT FOUND IN PLANT CELLS

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11
Q

PLANT CELLS

VACUOLE

Structure
1) It is filled with…by a single membrane called a…

Function
2) They make cells…so provide…
3) It’s a temporary store of s…and a..

A

1) fluid - tonoplast

2) turgid - support
3) sugar and amino acids

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12
Q

PLANT CELLS

CHLOROPLASTS

Structure
1) Surrounded by a…
2) Contains th…that are folded membranes embedded with…c…and ATP s…
3) It has a fluid filled s… that contains enzymes for..

Function
4) They have their own DNA and — ribosomes for…
5) site of..

A

1) double membrane
2) thylakoids - chlorophyll (for photosynthesis) and ATP synthase (to produce ATP)
3) stroma - photosynthesis

4) 70s ribosomes - synthesis of enzymes needed for photosynthesis
5) photosynthesis

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13
Q

PLANT CELLS

CELL WALL
1) found in…

Structure
2) made of microfibrils of the polymer…

Function
3) Contains many weak…
4) It is very strong which limits…
5) It also has plas… that are…that connect…to allow…

A

1) plant cells, fungi, algae and prokaryotes

2) cellulose

3) hydrogen bonds between cellulose fibrils
4) the volume of water that can move into a cell to stop osmotic lysis (bursting)
5) plasmodesmata - gaps in the cell walls - connect cell cytoplasms together - to allow easy movement of water-soluble molecules.

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14
Q

What are the differences between plant + animal cells?

A
  • cellulose cell wall V no cell wall
  • chloroplasts V no chloroplasts
  • large central vacuole V no vacuole
  • carbohydrates stored as starch V stored as glycogen
  • no centrioles V has centrioles
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15
Q

PROKARYOTIC CELLS

1) Prokaryotic cells don’t have a … or membrane bound..
2) The DNA of a prokaryotic cell is…and is not associated with…

It contains:
3) A cap—, which is the —– —–. a cell —- and cell ——–, and — ribosomes, also a fla—–, and pl—- and mes—–.
4) The DNA is free in the…

5) What is the function of capsule?
6) “ plasmid?
7) “ flagellum?
8) “ mesosomes?

9) THE CELL WALL IS MADE UP OF…

A

1) nucleus - organelles
2) circular - histones

3) capsule - outer layer, cell wall, cell membrane, 70S ribosomes, flagellum, plasmids and mesosomes.
4) cytoplasm

5) protects cell from immune systems - aids bacteria sticking together
6) circular DNA, contains antibiotic resistance genes
7) allows movement / propulsion
8) for ATP synthesis

9) murein or peptidoglycan

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16
Q

VIRUSES

1) They are not cells as they are not…
2) They are very a small and require a…
3) Contains…
4) Surrounded by a protein coat called a..
5) Has a.. proteins which enable it to bind to…
6) Has en.. that it used to replicate its ge…. and insert it into..

A

1) alive
2) living cell to replicate inside
3) DNA or RNA which can be single or double stranded
4) capsid
5) attachment proteins - host cells
6) enzymes - genetic information - the host cells DNA

17
Q

Eukaryotic cells produce and release proteins. Outline the role of organelles in the production, transport, release of proteins from eukaryotic cells. (6)

A

1) DNA in nucleus codes for the protein
2) Ribosomes / RER produces the protein
3) Mitochondria produce ATP for protein synthesis
4) Golgi packages and modifies it
5) Vesicles transport them
6) Vesicle fuses with C.S.M

18
Q

Describe the similarities and differences between the DNA in eukaryotic and prokaryotic cells. (7)

A

SIMILARITIES
1) Nucleotide structure is identical
2) Nucleotides joined by phosphodiester bonds
3) DNA in mitochondria / chloroplasts is similar to DNA in prokaryotes

DIFFERENCES
4) Eukaryotic DNA is longer
5) Eukaryotic DNA contains introns, prokaryotic DNA doesn’t
6) Eukaryotic DNA is linear, prokaryotic is circular
7) Eukaryotic is associated / bound to histones, prokaryotic isn’t.

19
Q

State three differences between DNA in the nucleus of a plant cell and DNA in a prokaryotic cell. (5)

A

1) Associated with histones V not associated
2) Linear V circular
3) No plasmids V plasmids
4) Introns V no introns
5) Longer V shorter

20
Q

Name two structures found in all bacteria that are not found in plant cells. (3)

A

1) Circular DNA
2) Murein / peptidoglycan cell wall
3) Smaller 70S ribosomes in the cytoplasm

21
Q

MICROSCOPES

light V electron

1) What is the illumination?
2) Focused by?
3) Maximum magnification?
4) Resolution?
5) Specimens have to be?
6) Staining process?

A

1) Light V beam of electrons.
2) Lens V electromagnets.
3) x1500 V x500,000.
4) 200nm (LOWER) V 1nm (HIGHER).
5) Living or dead V dead - fixed in resin and sliced thingly. Must be in a vacuum.
6) Easy - coloured dyes V complex - using heavy metals, can create artefacts.

22
Q

The shorter the wavelength, the better the…

Resolution is the ability to…

The resolution of a light microscope is limited by…

Electrons have a smaller…

A

…resolution

…distinguish two objects that are close together

…the wavelength of light

…wavelength than light so can see objects as small as ribosomes.

23
Q

Name 2 structures found within a eukaryotic cell that cannot be identified with a light microscope.

A

Mitochondria / ribosome / ER / lysosome / CSM

24
Q

Describe the principles and limitations of using a TEM (transmission) to investigate cell structure. (8)

A

PRINCIPLES
1) Electrons pass through thin specimen
2) Denser parts absorb more electrons
3) So denser parts appear darker
4) Electrons have short wavelength so give high resolution
LIMITATIONS
5) Cannot look at living cells / must be in a vacuum
6) Specimen must be very thin
7) artefacts present
8) Complex staining method

25
Q

Give one advantage of using a TEM rather than a SEM.

A

Higher resolution
OR
Allows internal structures in cells to be seen

26
Q

Give one advantage of using a SEM rather than a TEM.

A

Thin sections don’t need to be prepared
OR
3D images
OR
Shows surface of specimen

27
Q

Describe how you could make a temporary mount of a piece of plant tissue to observe the position of starch grains in the cells when using a light microscope. (4)

A

1) Add a drop of water to the microscope slide
2) Get a thin section of plant tissue and float on the drop of water
3) Stain with KI solution
4) Lower the cover slip using a mounted needle to avoid air bubbles

28
Q

Describe how the student could have used an eyepiece graticule to determine the mean diameter of stomata. (3)

A

1) Measure each stomata using an eyepiece stomata
2) Calibrate the eyepiece graticule against a stage micrometer
3) Take at least 5 measurements and calculate a mean (more measurements = more accurate + more representative)

29
Q

Scientists isolated mitochondria from liver cells. They broke the cells open in an ice-cold, buffered, isotonic solution. Explain why the solution was:
a) Ice-cold
b) Buffered
c) Isotonic

A

a) Reduce/prevent enzyme activity so organelles aren’t digested/damaged
b) Maintain a constant pH so proteins don’t denature
c) Prevents osmosis / no net movement of water / so organelle doesn’t shrivel/burst.

30
Q

Describe and explain how cell fractionation and centrifugation can be used to isolate mitochondria from a suspension of animal cells. (8)

What are the densest, second densest, and least densest organelles?

A

1) First, tissue is homogenised in a blender to break open cells and release the organelles
2) Then filter to remove large pieces of tissue (cellular debris)
3) Use isotonic solution to prevent osmotic damage to organelles
4) Use buffer to maintain pH and prevent enzyme/protein denaturation
5) Keep cold to prevent/reduce damage to organelles by enzymes
6) Use differential centridge at high speed to separate nuclei (heavy organelles first)
7) Re-spin supernatant after pellet of heavy organelles is removed, at higher speed to get mitochondria at pellet in the bottom
8) Observe pellet with a microscope to identify it.

Nuclei, mitochondria / chloroplast, ribosomes.

biology (17 decks)

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