A1 Cells Flashcards

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1
Q

What is the function of the Golgi apparatus?

A

Modifies proteins

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2
Q

What is the function of the mitochondria?

A

Release energy/ATP by aerobic respiration

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3
Q

Name the organelle shown on the electron micrograph

A

Mitochondria

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4
Q

What is the function of the ribosomes?

A

Protein synthesis

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5
Q

What is the function of the chloroplast?

A

Photosynthesis

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6
Q

Name the organelle shown on the electronmicrograph

A

Rough endoplasmic reticulum

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7
Q

Name 2 structures found in the nucleus

A

Chromosomes and nucleolus/nucleoli

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8
Q

What is the function of the cell membrane?

A

Controls which substances enter and leave the cell

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9
Q

What is the function of the Golgi vesicles?

A

Transports chemicals across the Golgi apparatus or to the cell membrane.

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10
Q

What is the function of the lysosome?

A

Hydrolyses dead or damaged organelles.

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11
Q

What is the function of the rough endoplasmic reticulum?

A

Makes and transports proteins

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12
Q

What is the function of the smooth endoplasmic reticulum?

A

Makes and transports steroids

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13
Q

What is the function of the cell wall?

A

Rigid outer covering to the plant cell. Supports the plant cell.

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14
Q

Name the chemical that makes up the cell wall in plants

A

Cellulose

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15
Q

Name the two chemical components of murein

A

Its is a glycoporotin

Protein and carbohydrate

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16
Q

Name the organelle shown on the electronmicrograph

A

Golgi apparatus

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17
Q

Name the chemical that makes up the cell wall in bacteria

A

Murein

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18
Q

Name the chemical that makes up the cell wall in fungi

A

Chitin

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19
Q

What is the function of the vacuole?

A

Stores cell sap. Keeps the cell turgid.

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20
Q

The epithelium cells of the small intestine have microvilli on them.

What is their function?

A

Increase surface area for absorption of digested food.

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21
Q

What is a tissue?

A

A group of similar specialised cells that perform a particular function.

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22
Q

What is an organ?

A

A group of tissues which perform a particular function

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23
Q

What is a system?

A

A group of organs which perform a particular function

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24
Q

Which are larger? Prokaryotic cells or eukaryotic cells?

A

Eukaryotic cells

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25
Q

Give three ways in which prokaryotic cells are different to eukaryotic cells

A

No membrane-bound organelles eg mitochondria
No nucleus
Smaller ribosomes
Cell wall made of glycoprotein not cellulose

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26
Q

Give 3 features that are found in prokaryotic cells and not eukaryotic cells

A

One or more plasmids
A capsule surrounding the cell
One or more flagella

27
Q

Give three features found in viruses

A

Genetic material
Capsid
Attachment protein

28
Q

Viruses are acellular. What does this mean?

A

Not made of cells

29
Q

Give 2 advantages of using a light microscope rather than an electron microscope

A

Can see living cells
Cell movement can be observed
Very few artefacts
Can see natural colour

30
Q

Give two advantages of using an electron microscope rather than a light microscope

A

Higher resolution
Higher magnification

31
Q

Why does an electron microscope give better resolution

than a light microscope?

A

Uses a shorter wavelength of the electromagnetic spectrum

32
Q

Give an advantage of a scanning electron microscope over a transmission electron microscope

A

3D images vs 2D images
Observe the surface of a structure

33
Q

Give an advantage of a transmission electron microscope over a scanning electron microscope

A

Higher resolution.
Observe internal structures in the cell

34
Q

Why are cells dead when viewed under an electron microscope?

A

High energy electrons damage cells
Vacuum needed
Cells dehydrated

35
Q

What does magnification mean?

A

How large the image is compared to real life

36
Q

What does resolution mean?

A

The smallest distance below which two discrete objects will be seen as one.

37
Q

What is the formula for calculating magnification?

A

Magnification = size of image/size of real object

38
Q

Describe how cell components can be separated in a lab.

A

Cell fractionation
Homogenate made by using a blender or mortar and pestle.
Filter - to remove cell debris
Centrifuge
Use different speeds to separate components of different density.

39
Q

How is pH maintained when separating cell components?

A

Buffer

40
Q

Why is an isotonic suspension needed whe separating cell components?

A

Prevent osmosis.
Prevent organelles shrinking or bursting

41
Q

How is enzyme activity reduced when separating cell components?

A

Ice cold conditions

42
Q

What is an artefact?

A

A change in the structure of an organelle during the preparation for observation under an electron microscope.

43
Q

In which type of cell would the 80S ribosome be found?

A

Eukaryotic cell

44
Q

Where would an 70S ribosome be found?

A

Prokaryotic cell
Mitochondria
Chloroplasts

45
Q

When observing cells under a microscope why does the specimen need to be thin?

A

Single layer of cells,
Allows light to pass through

46
Q

How is a temporary slide prepared for viewing?

A

Add drop of water to slide
Take a thin (1 cell thick) tissue sample
Place on glass slide (float on water)
Add stain
Lower coverslip onto slide using a mounted needle

47
Q

Give 3 rules when producing a scientific drawing

A

No shading
Single lines (no sketching)
Add labels/annotations
No crossed guidelines
Add magnification/scale bar

48
Q

How could the mean length of a cell be determined using an eye piece graticule?

A

Place micrometer on stage
Calibrate the graticle using a stage micrometer
Measure length of a random selection of cells using the graticle.
Calculate the mean

49
Q

Describe the structure of a lysosome

A

Sac surrounded by a single membrane
Proton pumps maintain acidic conditions
Contains hydrolytic enzymes called lysozyme

50
Q

Describe the structure of a ribosome

A

Made of RNA and protein
Free in the cytoplasm or attached to endoplasmic reticulum
Large subunit - joins amino acids
Small subunit - contains mRNA binding site

51
Q

Describe the structure of rough endoplasmic reticulum

A

Cisternae - network of tubes and flattened sacs
extends from nuclear membrane to cell membrane
Ribosomes attached to the outer surface

52
Q

Describe the structure of the plant cell wall

A

Made of cellulose microfibrils
Pores (plasmodesmata) allow molecules to pass between cells

53
Q

Describe the structure of the plant vacuole

A

Surrounded by a single membrane - tonoplast
Contains cell sap - water, mineral ions, enzymes, soluble pigments.

54
Q

Describe and explain the adaptions shown by an epithelium cell

of the small intestine

A
Folded membrane (microvilli) increase surface area for diffusion
Mnay mitochondria - large amount of ATP needed for active tramsport
55
Q

State the role of plasmids in prokaryotes

A

Small rind of DNA that carriers non-essential genes
Can be exchanged between bacteria

56
Q

State the role of the capsule in prokaryotes

A

Polysaccharide layer that
Prevents desiccation
Acts as a food reserve
Adhesive
Mechanical protection against phagocytosis

57
Q

Describe the structure of a viral particle

A

Linear genetic material (DNA or RNA)
Viral enzymes eg. reverse transcriptase
Surrounded by a capsid (protein coat)
No cytoplasm

58
Q

State the role of attachment proteins on viral particles

A

Enable virus to bind to complementary sites on host cell

59
Q

Describe how a transition electron microscope works

A

High energy beam of electrons pass through thin slice of specimen
More dense structures appear darker as they absorb more electrons
Focus image onto fluorescent screen or photographic plate using magnetic lenses

60
Q

Name the type of microscope used to produce this image of a pollen grain

A

Transmission electron microscope

61
Q

Describe how a scanning electron microscope works

A

Focus beam of electrons onto a specimens surface using electromagnetic lenses
Reflected electrons hit a collecting device and are amplified to produce an image on a photographic plate or fluorescent screen

62
Q

Describe how an optical microscope works

A

Lenses focus rays of light and magnify the view of a thin slice of specimen
Different structures absorb different amounts and wavelengths of light
Reflected light is transmitted to the observer via the objective and eyepiece lens

63
Q

Name the organelle shown on the electronmicrograph

A

Chloroplast

64
Q

Name the type of microscope used to produce this electron micrograph

A

Scanning electron microscope