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Biology-Corinna > 3.Cell Structure > Flashcards

3.Cell Structure Flashcards

1
Q

What is microscopy

A

The study using microscopes to produce an enlarged image of an object

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2
Q

What’s the equation for magnification

A

Image
———————— = magnification
Actual

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3
Q

What is resolving power/resultion

A

The minimum distance apart that two objects can be in order to be seen as separate images

Depends on wavelength or form of radiation used

The greater the resolution the clearer and more precise the image is

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4
Q

What happens during cell fractionation

A

Isolation of organelles
1-tissue placed in cold buffered solution that has same water potential as tissue
2-homogenation-cells broken up in homogeniser, resultant fluid (homogenise) filtered to remove any unbroken cells
3-ultracentrifugation-homogenate places in centrifuge and spun at slower speeds to separate out the heaviest layers, from sediment and is removed, then spun again and refiltered until all layers of cell have been removed.

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5
Q

Facts about electron microscope

A

Short wavelength = high resolving power

Uses electrons so beam can be focused

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6
Q

Facts about a Transmission electron microscope (TEM)

A

Beam of electrons produced by electron gun are focused by a condenser electromagnet

Needs very thin specimen so electrons can pass through
Resolving power 0.1nm
Parts absorb electrons so appear dark on screen

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7
Q

Why is the solution, a tissue is placed in during cell fractionation, cold buffered and same water potential?

A

Cold-reduce enzyme action to prevent the break down of organelles
Buffered-so pH doesn’t fluctuate and alter structure if organelles
Same W.P-prevents bursting or shrinking of organelles

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8
Q

What are the limitations of the TEM

A

Living organisms can’t be studied as in vacuum
Not in colour even though goes through complex staining
Extremely thing specimen
Artefacts may be in image that are from specimen

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9
Q

Facts about the scanning electron microscope (SEM)

A

Beam electrons directed straight onto surface from a above
Beam passed back n forth in regular pattern
Electrons catered by contours of specimen
Computer processes a 3D image
Resolving power of 20nm

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10
Q

Limitations of SEM

A

In vacuum so no living organisms
Complex staining process
Artefacts distort what we see-can’t be sure it’s real

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11
Q

What is apart of the nucleus

A

Nuclear envelope-double membrane, continues with ER
Nuclear pores-allow passage of molecules out of nucleus
Nucleoplasm-granular jelly that makes up bulk of nucleus
Chromosomes-protein bound linear dna
Nucleolus-manufactures ribosomal dna and assembles ribosomes

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12
Q

What’s the function of a nucleus

A

Acts as control centre through productions of mRNA, tRNA and protein synthesus
Retains genetic material of DNA and chromosomes
Manufactures ribosomal dna

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13
Q

What makes up mitochondria

A

Double mebrane-controls exit and entry of material
Cristae-inner folded membrane, for attachment of proteins and enzymes
Matrix-contains proteins, lipids, ribosomes and dna that allows mitochondria to control production of own proteins

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14
Q

Whats the function of mitochondria

A

Site of aerobic respiration and responsible for production of ATP

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15
Q

What makes up a chloroplast

A

Envelope-double plasma membrane, highly selective enter and exit
Grana-stack to form thylakoids, contain chlorphyll, first stage of photosynthesis
Stroma-fluid filled matrix, second stage photosynthesis, contain starch grains

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16
Q

What’s the function of chloroplasts

A

Grana membranes proved large surface area for the attachment of chlorophyll, enzymes carry out photosynthesis
Fluid of stroma contains the enzymes needed to make sugars
Chloroplasts contain dna so they can quickly manufacture some of the proteins needed for photosynthesis

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17
Q

What are the two types of endoplasmic Reticulum

A

Smooth er

Rough er

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18
Q

What are the differences between smooth ER and rough ER

A

Smooth has ribosomes, large area for protein synthesis and glycoproteins, pathway fir transport of materials through cell

Rough no ribosomes, more tubular, synthesis and storage and transport of lipids and carbohydrates

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19
Q

What makes up the Golgi apparatus

A

Cisternae-flattened sacs that stack up

Vesicles-small rounded hollow structures

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20
Q

What are the functions of the Golgi apparatus

A

Modification or proteins-add carbs to form glucolipids
Labels them-sorted and sent to right place of cell
Transported in vesicles-move to membrane and fuse with it and release
Produce secretory enzymes-like those by pancreas
Secrete carbs-like those used in making cell walls
Transfer and modify and store lipids
Form lysosomes

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21
Q

Facts about lysosomes

A

Produced by Golgi
Contain enzymes eg lysozymes and lipas es
They Isolate enzymes until they are needed

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22
Q

Functions of lysosomes

A

Hydrolyse material ingested eg phagocyte
Release enzymes to outside of cell
Digest worn out organelles
Autolysis-complete break down of cells after they’ve died

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23
Q

What are the two types of ribosomes

A

80S-eukaryotes bigger

70S-prokaryotes found in mitochondria, chloroplasts smaller

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24
Q

What’s the function of ribosomes

A

Site of protein synthesis

25
Q

What’s the structure of a cell wall

A

Plant cell walls structure is cellulose macrofibrils

Animal cell-large number of polysaccharides and has a middle lamella-thin layer marking boundary between adjacent walls and cements together

26
Q

What’s the function of the cell wall

A

Provide mechanical strength to prevent cell bursting under the pressure created by osmosis of water
Gives mechanical strength to plants as a whole
Allows water to pass along it and contributes to movement of water though plant

27
Q

What’s the cell wall of fungi made of

A

Chitin

28
Q

What is a vacuole

A

Fluid filled sac bound by a single membrane (tonoplast)

Contains a solution of mineral salts sugars amino acids waste and pigment

29
Q

What’s the function of a vacuole

A

Support herbaceous plants and herbaceous parts of woody plants by making them turgid

Sugars and amino acids act as temporary food store
Pigments colour petals to attract pollinating insects

30
Q

Relate cell ultrastructre to function

A

Each organelle has own function
Cells with lots of mitochondria produce lots of ATP used as energy
These cells have high rate of metabolism
The denser and more numerous Curtiss the greater the metabolic rate of cell

31
Q

What is cell specialisation

A

cells all initially have same functions

As mature they evolve and have fewer or more of certain organelles in order to be best adapted for function

32
Q

What are the atwo types of tissue

A

Epithelial and xylem

33
Q

What is a tissue

A

Group of cells with the same function that are grouped together for efficiency

34
Q

Facts about epithelial tissue

A

Found in animals-sheets of cells that line surface of organs
Have protective or secretory functions
Two types -ciliated and epithelial
Epithelial-thin surface line organs where diffusion occurs
Ciliated-lines ducts such as trachea, used to move mucus over epithelial surface

35
Q

What are organs

A

Where tissues aggregate into organs

Combo of tissues that are co ordinated to perform a variety of functions, often have on predominant major function

36
Q

An example of an organ and its many tissues in animal

A

Stomach
Muscles churn food
Epithelium protect stomach wall produce secretions
Connective tissue hold together all tissues

37
Q

Example of organ in plants

A 
Leaf tissue 
Palisade mesophyll photosynthesis 
Sponges mesophyll adapter for gaseous exchange
Phloem organic molecules away from leaf
Xylem transport water and ions into leaf
38
Q

What is an organ system

A

Group of organs working as a single unit

39
Q

What organs are in the digestive system

A

Salivary glands, oesophagus, stomach, duedenum, ileum, pancreas and liver

40
Q

What organs are in the circulatory system

A

Heart
Arteries
Veins

41
Q

What organs are part of respiratory system

A

Trachea
Bronchi
Lungs

42
Q

What are the main components of eukaryotic cells

A 
Distinct nucleus
Dna association with histones 
No plasmids
Linear dna 
Membrane bound organelles
Chloroplasts in plants 
Mitochondria 
80S 
No capsule
Cellulose cell wall
43
Q

What are the main components of prokaryotic cells

A 
No true nucleus 
Dna not associated with proteins
Circular dna and plasmids
No chloroplasts, chlorophyll associated in cell surface membrane
No membrane bound organelles
70S 
Mucilaginous layer-capsule
No mitochondria 
Cell wall of murein
44
Q

What’s the structure of a bacterial cell

A 
Cell wall of murein 
Mucilaginous capsule
Cell surface membrane
Cytoplasm
70S 
Glycogen and lipid droplets
Circular dna and plasmids
45
Q

Structure of viruses

A 
Acellular
Non living
Nucleic acids enclosed in capsid
Lipid envelope or capsid
Attachment proteins to allow to attach to host cells and replication
46
Q

What is phase on of mitosis

A

Interphase
Cell doesn’t divide
3 stages
G1-growth of cell, doubles size, contents duplicate, proteins synthesis
S-dna replication (semi conservative)
G2-cell continues to grow, checks for errors, prep for mitosis

47
Q

Definition of mitosis

A

The nuclear division of. Parent cell to produce two genetically identical daughter cells

48
Q

What happens in phase two of mitosis

A

Nuclear division

thas 4 stages -PMAT

49
Q

What happens during prophase

A

1-chromosomes condense-shorter n thicker
2-nuclear envelope and nucleoli disintegrate
3-centrioles move to opposite poles of cell
4-mitotic spindle fibres form

50
Q

What happens during metaphase

A

Chromosomes which are made up of two chromatids joined by centromere
1-chromosomes line up at metaphase plate at equator of cells
2-attach fo spindle fibres via centromere

51
Q

What happens during anaphase

A

Spindle fibres contract

Sister chromatids pulled apart and pulled to opposite poles

52
Q

What happens during telophase

A

Spindle fibres disintegrate
Nuclear envelope and nucleolus reform around chromosomes
Chromosomes diffuse
Cleavage furrow begins to form

53
Q

What happens in phase 3 of mitosis

A

Cytokinesis

Cytoplasm splits and forms two daughter nuclei

54
Q

How do viruses replicate

A
  • Attach to host cell via attachment proteins and release their nucleic acids into host cells
  • nucleic acid provides the instructions for host cells metabolic process to produce viral components, nucleic acids and structural proteins needed to assemble new viruses
55
Q

What is cancer caused by

A

Growth disorder of cells due to damage to genes that control cell growth

Leads to uncontrolled growth and division of cells as a result a group of abnormal cells form TUMOUR

56
Q

Why do most cells divide?

A

For growth and repair

57
Q

What’s the difference between malignant tumours and benign tumours

A

Less compact and grow faster and cancerous

More compact grow slower non cancerous

58
Q

How is cancer treated

A

Involves killing cellls by blocking part of cell cycle eg drugs that prevent dna replication or inhibit metaphase stage by interfering with mitotic spindle formations

59
Q

What are the problems with the treatment of cancer

A

Disrupt normal cell cycles

Rapidly diving cells vulnerable to damage

Biology-Corinna (22 decks)

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