2.1.1 - Cell Structure (set A - Euckaryotic Cell Organelle) Flashcards

1
Q

Define a prokaryotic organism?

A

Prokaryotes are organisms whose cells lack a nucleus and other organelles, prokaryotes are divided into two distinct groups: the bacteria and the archaea

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2
Q

Define eukaryotic organisms?

A

A eukaryote is any organism consisting of one or more cells that contain DNA in a membrane-bound nucleus, separate from the cytoplasm - examples are plant, animal, fungi and protists

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3
Q

Explain the structure of the nucleus, make reference to all key parts?

A

Large organelle containing a dense structure called the Nucleolus and chromatin (DNA) and is surrounded by the semipermeable Nuclear Envelope, a structure composed of an inner and outer nuclear membrane which contain a number of nuclear pores

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4
Q

Explain the main function of the nucleus?

A
  • Controls the cells activities by controlling the transcription of DNA (instructions needed for making proteins), gene expression mitosis and semiconservative replication
  • contains DNA coiled around chromatin into chromosomes
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5
Q

Explain what the plant cell wall is?

A

Rigid structure that surrounds plant cells, made of cellulose microfibrils for mechanical support

  • plasmodesmata form part of apoplast pathway to allow molecules to pass between cells
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6
Q

Explain the function of the cell wall?

A

The cell wall gives the cell structure, which prevents it from changing shape. It also offers a small level of added protection.

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7
Q

Explain what the plasma cell surface membrane is?

A

The membrane found on the surface of animal cells and the inside the cell wall of plant cells - the cell membrane consists of a lipid bilayer that is semipermeable - composed of proteins and lipids

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8
Q

Explain the function of plasma cell surface membrane?

A

Regulates the movement of substances into and out of the cell - has receptor molecules on it which respond to chemicals like hormones

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9
Q

What is the lysosome?

A

A round organelle suspended by a membrane, with no clear internal structure - acts as rubbish bin as they break down excess or worn-out cell parts with digestive enzymes

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10
Q

What is the function of the lysosome?

A

Contains hydrolytic enzymes kept separate from the cytoplasm by the surrounding membrane, and can be used to digest invading cells or to break down worn out components of the cell

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11
Q

What are ribosomes?

A

very small organelle that either floats free in the cytoplasm or are attached to the rough endoplasmic reticulum - made up of proteins and RNA (not surrounded by a membrane)

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12
Q

What is the function of ribosomes?

A

The site where proteins are made

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13
Q

What is the rough endoplasmic reticulum (RER)?

A

The RER is a membrane bound organelle located near the nucleus It is made up of thin, fluid filled membranes that are stacked together (cisternae) and is covered with ribosomes

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14
Q

What is the function of rough endoplasmic reticulum (RER)?

A

Folds and processes proteins that have been made at ribosomes - the site of protein synthesis

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15
Q

What is the smooth endoplasmic reticulum (SER)?

A

Has the same structure as the rough endoplasmic reticulum but does not have ribosomes

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16
Q

What is the function of the smooth endoplasmic reticulum (SER)?

A

Responsible for carbohydrate and lipid synthesis, and storage

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17
Q

What is the vesicle?

A

A small fluid-filled sac in the cytoplasm, surrounded by a membrane

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18
Q

What is the function of the vesicle?

A

Transports substance in and out of the cell (via the plasma membrane) and between organelles

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19
Q

Where are vesicles formed?

A

some are formed by the Golgi apparatus or the endoplasmic reticulum while others are formed by the plasma membrane

20
Q

What are mitochondria?

A

Usually oval-shaped and have a double membrane - the inner one if folded to form structure called cristae inside is the matrix which contains enzymes involved in respiration

21
Q

what is the function of mitochondria?

A

The site of aerobic respiration here ATP is produced - they’re found in large numbers in cells that are very active and require lots of energy such as muscle,brain or liver cells

22
Q

What is the Golgi apparatus?

A

A group of fluid-filled membrane-bound, flattened sacs which have vesicles at the edges

23
Q

What is the function of the Golgi apparatus?

A
  • Processes and modifies new lipids and proteins and packages them into vesicles
  • makes lysosomes
  • allows internal transport
24
Q

What are chloroplast?

A

Small, flattened structures found in plant cells they are surrounded by a double membrane - have thylakoid membranes inside which are stacked up in some parts of the chloroplast to form grana which are linked together by lamellae

25
Q

What is the function of chloroplasts?

A

The site where photosynthesis takes place - some parts of photosynthesis happens in the grana, other parts happen in the stroma

26
Q

What are stoma?

A

located in the chloroplast and responsible for some photosynthesis - is a thick fluid

27
Q

What are centriole?

A

Small, hollow cylinders made of microtubules found in animal cells, but only some plant cells located in the cytoplasm

28
Q

What are 3 functions of centriole?

A
  • They engage in the arrangement of mitotic spindles during cell division
  • organises the microtubules in the cytoplasm
  • regulate the position of the nucleus and other organelles in the cell.
29
Q

What are cilia?

A

Small ‘hair like’ structures found on the surface membranes of some animal cells - have an outer membrane and a ring of nine pairs of protein microtubules inside with two microtubules in the middle

30
Q

What is the function of cilia?

A

Microtubules allow the cilia to move - the movement is used by the cell to move substances along the cell surface - located in the bronchus and moves microbes and debris up and away from the lungs

31
Q

What are flagellum?

A

Flagella on eukaryotic cells are like cilia but longer, stick out of the cells surface and are surrounded by plasma membrane - have two microtubules in the centre surrounded by nine pairs around the edge

32
Q

What is the function of flagellum?

A

The microtubules contract to make the flagellum move - for example the tail on sperm cells allow it to swim to the egg

33
Q

What are cytoskeletons?

A

The cytoskeleton is a network of proteins that forms the internal framework for the cell

34
Q

What are the three components of the cytoskeleton?

A
  • microfilaments
  • microtubules
  • intermediate fibres
35
Q

What are microfilaments?

A

Fibres made from the protein ‘actin’ they are responsible for movement of the cell and cytoplasm during Cytokine

36
Q

What are microtubules?

A

Formed by protein ‘tubulin’, they polymerise to form tubes that determine the shape of the cell

37
Q

What are intermediate fibres?

A

Gives strength to cells and helps maintain integrity

38
Q

What is the structure of the cellulose cell wall?

A

Made of a complex carbohydrate (B-cellulose microfibril) the cell wall is fully permeable to substances - a thin layer called the middle lamella marks the boundary between adjacent cell walls

39
Q

What is the function of the cellulose cell wall?

A
  • gives the plant mechanical strength
  • gives the plant support and its shape
  • contents of the plant can ‘push’ against the cell wall (turgid cell), giving the plant support
40
Q

What is the structure of the large permanent vacuole?

A

Single membrane bound (membrane called a ‘tonoplast’) contains cell sap - has selectively permeable barrier

  • membrane allows control of certain molecules
41
Q

What is the function of large permanent vacuole?

A
  • stores cell sap
  • supports herbaceous plants by making cells turgid
  • sugar and amino acids act as temporary food source
42
Q

What are 5 features of prokaryotes?

A
  • extremely small cells, smaller then eukaryotes
  • DNA is circular and free in the cytoplasm
  • no nucleus
  • no membrane-bound organelles or mitochondria
  • small ribosomes
43
Q

What are 4 features of eukaryotes?

A
  • larger cells
  • DNA is linear and enclosed inside the nucleus
  • mitochondria and other membrane-bound organelle present
  • large ribosomes
44
Q

how are mitochondrion adapted for increased reactions?

A

Have crista which are finger like folds in the inner membrane of a mitochondrion, its purpose is to increase the surface area to allow for more reactions to take place

45
Q

What are cisternae and which organelle of a cell are they located?

A

Stacks of membrane bound (fluid filled) sacs which form sheets found in the endoplasmic reticulum and Golgi apparatus

46
Q

What are membranes, what is their function?

A

Membranes are selectively permeable and control the movement of substances into and out of the cell and organelles