Cells Flashcards

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1
Q

What is structure and function of the nucleus?

A

Nucleus - site of DNA replication and transcription and contains genetic code for each cell

Nuclear envelope - double membrane

Nuclear pores - holes on outside

Nucleoplasm - jelly like material on outside

Chromosomes - protein bound, linear DNA

Nucleolus - small sphere where RNA production occurs and makes ribosomes

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2
Q

What is structure and function of golgi apparatus?

A

Golgi apparatus

Structure: Folded membranes

Secretary vesicles pinch off cristae

Function:

Make glycoproteins by adding carbohydrates to proteins

They are then packaged into golgi vesicles and are transported to cell surface membrane

They then fuse with the membrane and the contents are released

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3
Q

What is structure and function of mitochondria?

A

Structure:

Double membrane

Inner membrane called the cristae

Fluid centre called the matrix

Loop of mitochondria RNA

Function:

Site of ATP production and aerobic respiration

DNA to code for enzymes needed in respiration

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4
Q

What are the structure and function of chloroplasts?

A

Structure:

Surrounded by double membrane

Contain thylakoids - folded membranes embedded with pigment

Stroma contain enzymes for photosynthesis

Function:

Site for photosynthesis

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5
Q

What is structure and function of a plasma membrane?

A

Structure:

Phospholipid bilayer: molecules embed within and attached on the outside

Function:

Controls entry and exit of molecules

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6
Q

What is function and structure of the Endoplasmic reticulum?

A

Structure:

RER and SER both have cristae

RER contains ribosomes on outside

Function:

RER - Site of protein synthesis

SER - synthesis and stores lipids and carbohydrates

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7
Q

What is structure and function of lysosomes?

A

Structure:

Bags of digestive enzymes

Function:

Secrete enzymes to outside of cell to destroy materials

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8
Q

What is structure and function of ribosomes?

A

Structure:

80s larger ribosomes found in eukaryotic cells

70s smaller ribosomes found in prokaryotic cells

Function:

Site of protein synthesis

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9
Q

What is structure and function of vacuole?

A

Structure:

Filled with fluid surrounded by single membrane

Function:

Make cells turgid for support and pigments colour petals to attract pollinators

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10
Q

What is structure and function of cell wall?

A

Structure:

Plants: made of microfibrils of cellulose polymer

Fungi - made of chitin

Function - provide structural strength to wall

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11
Q

What are differences between prokaryotic and eukaryotic cells?

A

Prokaryotic cells are smaller
Have no nucleus
No membrane bound organelles
Smaller ribosomes
Cell wall made of murein

Some prokaryotic cells contain
Plasmids
Capsule around the cell
Flagella

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12
Q

What is murein?

A

A glycoprotein

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13
Q

What do prokaryotic cells have instead of a nucleus?

A

Single circular DNA molecule which is free from cytoplasm

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14
Q

What is binary fission of prokaryotes?

A
  1. DNA and plasmids replicate.
  2. Cell elongates and DNA moves to opposite poles of cell
  3. Cytoplasm begins to divide and new cell wall forms
  4. Produces 2 daughter cells. Each contain identical DNA loop but have different number of plasmids as they don’t split evenly
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15
Q

What is a bacteriophage and its properties?

A

Virus which attacks bacteria

1000x smaller than bacteria and needs living cell

Consists of RNA protected by protein coat called capsid

Attachment proteins attach to host cells to recognise them

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16
Q

What is process of virus replication?

A
  1. Detects host cell by recognising protein marker on membrane and attach with attachment proteins
  2. Virus injects genetic material into cell
  3. Cell reproduces genetic material and reads it creating new viral proteins
  4. Virus leaves cell by destroying cell and affects different cells
17
Q

What is function of plasmids, capsule and the flagella?

A

Plasmids are small loops of DNA which only carry a few genes

Capsule - slimy layer made of protein which prevents bacteria drying out

Flagella - rotates allowing bacteria to move

18
Q

What is cell fractionation?

A

Where cells are broken up to release different organisms they contain

19
Q

How are cells separated?

A

They are separated based on their sizes via gravity

20
Q

What are steps of ultracentrifugation?

A

Step 1 (homogenisation) - cells are broken using a blender - cells must be in a solution

Step 2 (filtration) - blended material is filtered to remove large debris

Step 3 (centrifugation) - Solution is placed in a centrifuge and uses gravity to separate organelles by weight by spinning at different speeds

Each time, the liquid is removed (supernatant) and process is repeated at faster speeds until all organelles are separated

21
Q

What type of organelles are removed at slower speeds?

A

More dense organelles

22
Q

Which organelles separate first?

A
  1. Nuclei
  2. Chloroplasts
  3. Mitochondria
  4. Lysosomes
  5. Endoplasmic reticulum
  6. Ribosomes
23
Q

What properties must solution have in ultracentrifugation?

A

Solution must be:

Ice cold - reduces enzyme activity which may break down cells

Buffered - reduces change in ph so enzymes don’t denature

Isotonic - prevents cells bursting via osmosis - water potential inside and out is equal

24
Q

What are advantages/disadvantages of light microscopes?

A

A: Cheap and available in schools

Can observe live specimen

DA: Fewer details of cell structure can be observed

0.2 um resolution

X1500 magnification limit

25
Q

What are advantages/disadvantages of electron microscopes?

A

A: 2 x 10(6) magnification limit

Can produce 3D images

Resolution of 0.1 nm limit

DA: Expensive and not available in schools

Can’t be used for live specimen