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Cytology > Cell Organisation > Flashcards

Cell Organisation Flashcards

1
Q

Structure of prokaryotic cells

A

Contain no nucleus

No cell membrane

DNA/RNA is located in cytoplasm

Contains a cell wall

Divides through binary fission (rapid mitosis)

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2
Q

Structure of eukaryotic cells

A

Contain a nucleus & membrane bound organelles

Only plants & fungi contain a cell wall

Division involves mitosis

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3
Q

What is a cell membrane

A

A flexible, semi-permeable membrane (phospholipid bilayer) that separates the cells external & internal environment

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4
Q

Transmembrane proteins (emdedded in cell membranes) help to perform

A

Movement of substances in/out of cells

Immunological identity (helps immune system to recognise our own cells)

Receptors (recognition site for
hormones)

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5
Q

What is a cell junction

A

Contact/communication points between adjacent cell membranes of tightly packed cells

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6
Q

Examples of tight junctions

A

Found in stomach, intestines & bladder

Where the transmembrane protein fuse cells together to reinforce the junctions & seal off passageways to prevent leaking

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7
Q

Examples of gap junctions

A

Small fluid-filled tunnels between neighbouring cells

Nerves

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8
Q

Which body cells do not have a nucleus

A

Red blood cells

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9
Q

What does the nucleolus produce

A

RNA (Ribonucleic Acid)

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10
Q

What are chromosomes

A

Thread-like structures of nucleic acids & proteins found in the nucleus of most living cells, carrying genetic information
Coiled up DNA

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11
Q

How many chromosomes are in each cell in the body (apart from gametes)

A

46

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12
Q

How many chromosomes are in gametes

A

23 pairs

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13
Q

What are the two pairs of male & female gametes

A

Male - XY

Female - XX

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14
Q

Why are males more likely to develop genetic diseases

A

If there is a disease on the single X chromosome, the Y cannot counteract it unlike female gametes

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15
Q

What are histones

A

Proteins that DNA form a double helix around

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16
Q

What is the meaning of epigenetics

A

Where enviornments can impact which genes are switched on

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17
Q

What is the cytoskeleton

A

A network of protein filaments that extends through the cytosol

18
Q

What do the protein filaments in the cytoskeleton assist

A

Help cells generate movement eg enables white blood cells to migrate to sites of injury

In muscle cells they are the organelle that enables muscle contraction

Physical support & shape

Assists in cell division

19
Q

What is ATP

A

Adenosine Triphosphate - the energy currency of somatic cells

20
Q

What processes do mitochondria undergo

A

Use oxygen & nutrients such as glucose to create ATP via aerobic respiration

21
Q

What are ribosomes

A

The sites of protein synthesis containing high quantities of RNA
They are either free ‘mobile’ in cytoplasm or bound to rough endoplasmic reticulum

22
Q

the difference between free ribosomes & stationary

A

Free ribosomes make protein for inside the cell whereas those on the rough endoplasmic reticulum make proteins for outside the cell

23
Q

What is the Endoplasmic Reticulum (ER)

A

A network of membranes in the form of flattened sacs which extends from the nucleur envelope throughout the cytoplasm to the cell membrane

Endoplasmic- within plasma
Reticulum- network

24
Q

Compare the two types of ER

A

Rough ER is continuous with the nucleur membrane & its outer surface is studded with ribosomes which synthesises & transports proteins
Smooth ER contains no ribosomes but instead unique enzymes which perform lipid & hormone synthesis, in the liver enzymes detoxify & in muscle it releases calcium for contraction

25
Q

What is the function of the golgi apparatus

A

Modifies, sorts, packages & transports proteins received from the rough ER
Enzymes modify the proteins & they bud off in transport vesicles
It consists of flattened membranous sacs & most cells have several Golgi

26
Q

What is the function of lysosomes

A

Vesicles that contain as many as 60 powerful enzymes which can breakdown a variety of molecules
They recycle worn out organelles by engullfing, digesting & returning components to the cytosol for reuse
Also used to digest foreign cells
And release enzymes externally eg with sperm to assist egg entry

Lyso- breakdown
Soma-body

27
Q

Process of mitosis

A

Full set of chromosomes is first duplicated & then evenly distributed into both daughter cells
1 division creating 2 identical diploid daughter cells
Used for growth & repair
But we are Born with a set number of brain & muscle cells & egg cells which cannot undergo mitosis

28
Q

Process of meiosis

A

Gametes produce 4 haploid nucleus (half) cells through 2 divisions
The 4 cells produced are non-identical

29
Q

What is a zygote

A

Diploid cells which have 2 copies of chromosomes (23 pairs)

Zygote leads onto undergoing mitosis which develops into an embryo & eventually a foetus

30
Q

The four amino acids in DNA sequences

A

Adenine
Cytosine
Thymine
Guanine

31
Q

The two phases of protein synthesis

A
  1. Transcription - copy of one gene made into mRNA (messenger RNA) which travels out of the nucleus to a ribosome
  2. Translation - ribosomes read the code & produces a chain of amino acids to form the required protein

(If protein used within cell distributed by free ribsomones, if outside of cell by the Golgi)

32
Q

Passive transport of molecules & examples

A

Movement of substances from an area of HIGH - low concentration (moving down the conc gradient) & requires no energy

Eg
Diffusion ie gases
Osmosis
Facilitated diffusion

33
Q

Active transport of molecules & examples

A

Movement of substances from an area of LOW - high concentration (up the conc gradient) & requires ATP energy

Egs
Pumps (sodium potassium pump)-
Endocytosis
Exocytosis

34
Q

What is pinocytosis

A

Specialised cells that drink fluids

35
Q

What is diffusion

A

Movement of molecules down the conc gradient such as gases eg oxygen

36
Q

What is osmosis

A

Movement of water down the conc gradient

Dilutes concentrated & concentrates diluted

37
Q

What is facilitated diffusion

A

Movement down the conc gradient aided by transmembrane proteins
For larger substances eg glucose & charged molecules

38
Q

What are active transport pumps

A

Use protein pumps in the cell membrane to allow specific molecules up the conc gradient
Sodium potassium pump important for nerves

39
Q

What is endocytosis

A

Engulfing of particles into the cell through cell membrane extensions
Either phagocytosis or pinocytosis

40
Q

What is exocytosis

A

Removal of waste from the cell

Fuses with membrane before being expelled

Cytology (5 decks)

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