Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology‎ > Section 2- Cells > Flashcards

Section 2- Cells Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is a Eukaryote?

A

These are (mostly) multicellular organisms made up of eukaryotic cells like animals, plants, fungi, and protists.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a Prokaryote?

A

These are single-celled organisms made up of prokaryotic cells like bacteria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are eukaryotic cells?

A

These cells are more complex, contain membrane-bound organelles and have DNA in the form of chromosomes within a nucleus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is in an animal cell?

A
  1. Nucleus
  2. nucleolus
  3. smooth endoplasmic reticulum
  4. rough endoplasmic reticulum
  5. Golgi apparatus
  6. golgi vessels
  7. Ribosomes
  8. Lyosomes
  9. Mitochondria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

State the relationship between a system and specialised cells.

A

Specialised cells make up tissues that perform a specific function. These tissues then form organs, and these organs that carry out a specific function are organ systems.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the structure of the cell-surface membranes.

A

The structure is a ‘Fluid mosaic’ phospholipid bilayer with extrinsic and intrinsic proteins embedded.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the Function of the cell-surface membrane.

A
  1. isolates cytoplasm from the extracellular environment
  2. selectively permeable to regulate the transport of substances
  3. involved in cell signalling/cell recognition.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain the role of cholesterol, glycoproteins and glycolipids in the cell surface membrane.

A

Cholesterol: steroid molecule connects phospholipids and reduces fluidity.
Glycoproteins: cell signalling, cell recognition and binding cells together,
Glycolipids: cell signalling and cell recognition.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the structure of the nucleus.

A
  1. Surrounded by a nuclear envelope, a semi-permeable double membrane
  2. Nuclear pores allow substances to enter/ exit.
  3. Dense nucleolus made of RNA and proteins assembles ribosomes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the function of the nucleus.

A
  1. Contains DNA coiled around chromatin into chromosomes
  2. Controls cellular processes: Gene expression determines specialisation and site of mRNA transcription, mitosis, and semiconservative replication.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the structure of a mitochondrion.

A
  1. Surrounded by a double membrane. The Folded inner membrane forms cristae which is the site of the electron transport chain.
  2. Fluid matrix: contains mitochondrial DNA, respiratory enzymes, lipids, and proteins.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the structure of a chloroplast.

A
  1. Vesicular plastid with double membrane
  2. Thylakoids: flattened disks stacked to form grana; contain photosystems with chlorophyll.
    3: Intergrana Lamellae: tubes attach thylakoids in adjacent grana.
    Stroma: fluid-filled matrix.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

State the function of mitochondria

A

Site of aerobic respiration to produce ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

State the function of chloroplasts

A

Site of photosynthesis to convert solar energy to chemical energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the structure of the Golgi apparatus.

A
  1. The planar stack of membrane-bound, flattened sac’s cis face aligns with the respiratory exchange ratio.
  2. Molecules are processed in cisternae vesicles bud off trans face via exocytosis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the function of the Golgi apparatus.

A
  1. modifies and packages proteins for export.
  2. synthesised glycoproteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the structure of a lysosome.

A
  1. Sac surrounded by a single membrane
  2. The embedded H+ pump maintains acidic conditions.
  3. Contains digestive hydrolase enzymes
  4. Glycoprotein coat protects cell interior.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the Function of a lysosome

A
  1. Digest contents of phagosome
  2. exocytosis of digestive enzymes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the structure of a ribosome.

A
  1. Formed of protein and rRNA
  2. pree in cytoplasm or attached to Endoplasmic reticulum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe the function of a ribosome.

A
  1. site of protein synthesis via translation
  2. A large subunit joins amino acids
  3. small subunit contains mRNA binding site.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe the structure and function of the endoplasmic reticulum.

A
  1. Cisternae: a network of tubules and flattened sacs that extends from the cell membrane through the cytoplasm and connects to the nuclear envelope
  2. Rough ER: many ribosomes attached for protein synthesis and transport.
  3. Smooth ER: Lipid synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe the structure of the cell wall.

A
  1. Bacteria: made of the polysaccharide murein
  2. Plants: Made of cellulose microfibrils. plasmodesmata allow molecules to pass between cells, middle lamella acts as a boundary between adjacent cell walls.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

State the functions of the cell wall

A
  1. mechanical strength and support
  2. Physical barrier against pathogens
  3. Part of apoplast pathway (plants) to enable easy diffusion of water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe the structure and function of the cell vacuole in plants.

A
  1. Surrounded by a single membrane: the tonoplast
  2. contains cell sap: mineral ions, water, enzymes, and soluble pigments.
    - Controls turgor pressure
    - Absorbs and hydrolysis potentially harmful substances to detoxify cytoplasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Explain some common cell adaptations.

A
  1. Folded membrane or microvilli increase surface e.g. for diffusion.
  2. Many mitochondria = large amounts of ATP for active transport.
  3. Walls one cell thick to reduce the distance of diffusion pathway.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

State the role of plasmids in prokaryotes.

A
  1. Small ring of DNA that carries non-essential genes.
  2. Can be exchanged between bacterial cells via conjugation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

State the role of flagella in prokaryotes.

A

Rotating cells (usually unicellular) organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

State the role of the capsule in prokaryotes

A

!. Prevents desiccation
2. Acts as a food reserve.
3. Provides mechanical protection against phagocytosis and external chemicals.
4. sticks cells together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

similarities between eukaryotic and prokaryotic cells?

A

Both have:
1. cell membrane
2. Cytoplasm
3. Ribosomes (don’t count as an organelle as not membrane-bound)

30
Q

Contrast Eukaryotic and Prokaryotic cells.

A

Prokaryotic :
unicellular. no membrane-bound organelles. no nucleus
circular DNA not associated with proteins
Small ribosomes (70s)/ 80s ribosomes eukaryotic
Binary fission - always asexual reproduction. / mitosis and meiosis bot a/ sexusl
murein cell walls cellulose /chitin cell walls
Capsule, sometimes plasmids and cytoskeleton.

31
Q

Why are viruses referred to as ‘particles’ instead of cells

A

Acellular and non-living: contain no cytoplasm and cannot self reproduce also no metabolism.

32
Q

Describe the structure of a viral particle

A
  1. Linear genetic material (DNA or RNA) and viral enzymes e.g. reverse transcriptase.
  2. surrounded by capsid (protein coat made of capsomeres
  3. no cytoplasm
33
Q

Describe the structure of an enveloped virus.

A
  1. Simple virus surrounded by matrix protein
  2. Matrix protein surrounded by envelope
  3. Attachment proteins on surface
34
Q

State the role of the capsid on viral particles

A
  1. protect nucleic acid from degradation by restricting endonucleases.
  2. surface sutes enable viral particle to bind to and enter host cells or inject their genetic material.
35
Q

State the role of attachment protein on viral particles

A

Enable viral particles to bind to complementary sites on host cell: entry vial endosymbiosis

36
Q

Describe how optical microscopes work.

A
  1. lenses focus rays of light and magnify the view of a thin slice of the specimen.
  2. different structures absorb different amounts and wavelengths of light
  3. reflected light is transmitted to the observer via the objective lens and eyepiece
37
Q

Outline how a student could prepare a temporary amount of tissue for an optical microscope.

A
  1. obtain a thin section of tissue e.g. using ultratome or by maceration
  2. place plant tissue in a drop of water
  3. stain tissue on the slide to make structures visible
  4. add coverslip using a mounted needle at 45 degrees to avoid trapping air bubbles
38
Q

Suggest the advantages and limitations of using an optical microscope

A

+ colour image
+can show living structures
+ affordable apparatus
- 2d image
- lower resolution that electron microscopes = unable to see ultrastructures

39
Q

Describe how a transmission electron microscope works.

A
  1. pass a high beam of electrons through a thin slice of the specimen
  2. more dense structures appear darker since they absorb more electrons
  3. focus the image onto a fluorescent screen or photographic plate using magnetic lenses
40
Q

Suggest the advantages and limitations of using a TEM

A

+ electrons have a shorter wavelength than light= high resolution so visible ultrastructures
+ high magnification x500000
- 2d image
-requires a vacuum
-extensive preparation may introduce artefacts
- no color image

41
Q

Describe hoe a scanning electron microscope (SEM) works.

A
  1. focus a beam of electrons onto a specimen’s surface using electromagnetic lenses
  2. Reflected electrons hit a collecting device and are amplified to produce an image on a photographic plate
42
Q

Suggest the advantages and limitations of using an SEM

A

+ 3d image
+ electrons have a shorter wavelength than light = high resolution
- requires a vacuum = cannot show living structures
- no colour image
-only shows the outer surface.

43
Q

Define magnification and resolution

A

Magnification: the factor by which the image is larger than the actual specimen
Resolution: smallest separation distance at which 2 separate structures can be distinguished from each other

44
Q

Explain how to use an eyepiece graticule and stage micrometre to measure the size of a structure.

A
  1. place on micrometer on stage to calibrate the eyepiece graticule
  2. line up scales on graticule micrometre. count how many graticule divisions are in 100um on the micrometre
  3. length of 1 eyepiece division = 100um / number of divisions
  4. use calibrated values to calculate the actual length of structures
45
Q

State an equation to calculate the actual size of a structure from microscopy.

A

actual size = image size/magnification

46
Q

Outline what happens during cell fractionation and ultracentrifugation.

A
  1. mince and homogenize tissue to break open cells and release organelles
  2. filter homogenate to remove debris
  3. perform differential centrifugation
    a) spin homogenate in a centrifuge
    b) the most dense organelles in the mixture form a pellet
    c) filter off the supernatant and spin again at a higher speed
47
Q

State the order of sedimentation of organelles during differential centrifugation

A

most dense—> least dense
nucleus–> mitochondria-> lysosomes -> RER-> plasma membrane -> SER-> ribosomes

48
Q

Explain why fractionated cells are kept in a cold buffered, isotonic solution.

A

Cold: slow action of hydrolase enzymes.
Buffered: maintain constant PH
isotonic: prevent osmotic lysis/ shrinking of organelles.

49
Q

State what the cell cycle is and outline its stages.

A

Cycle of division with intermediate growth periods.
1. interphase
2. mitosis or meiosis
3. cytokinesis.

50
Q

Explain why the cell cycle does not happen in some cells.

A

After differentiation, some types of cells in multicellular organisms (e.g. neurons) no longer can divide.

51
Q

What is the difference between the cell cycle and mitosis?

A

The cell cycle includes a growth period between divisions; mitosis is only 10% of the cycle and refers only to nuclear division.

52
Q

state what the cell cycle is and outline its stages.

A
  • interphase
  • mitosis or meisos
  • cytokinesis
53
Q

Why dosent that cell cycle happen in some cells?

A
  • after differentiation some types of cell in multicelluar organisms (e.g. neurons) no longer have the ability to divide.
54
Q

Outline what happens during interphase.

A

G1: cell makes proteins for replication and cell size doubles
S: Dna replicates chromosomes consist of 2 sister chromatids joined at a centromere
G2: organelles divide.

55
Q

What is the purpose of mitosis?

A

Produces 2 genetically identical daughter cells for growth, repair and aesexual reproduction.

56
Q

Name the stages of mitosis

A
  • Prophase
  • Metaphase
  • Anaphase
  • telophase
57
Q

What happens during Prophase?

A
  • Chromosomes condense , becomming visible. they are x shaped with two sister chromatids joined at centomere
  • Centrioles moves to opposite poles of cell (animal) and mitotic spindle fibres form
  • Nuclear envelope and nucleolus break down so the chromosomes free in cytoplasm.
58
Q

What happens during metaphase?

A
  • sister chromatids line up at cell equator, attached to the mitotic spindle by their centromeres.
59
Q

What happens during Anaphase?

A
  • Using energy from atp hydrolysis,
  • spindle fibres contract and the centromeres divide
  • sister chromatides seperate into two distinct chromosomes and are pulled to opposite poles of the cell
  • spindle fibres break down
60
Q

What happens during telophase?

A
  • chromosomes decondense
  • new nuclear envelope form around each new set of chromosomes this makes two new nuclei.
61
Q

What is the procedure for a root tip sqaush experiment?

A
  • prepare a tempoary mount of root tissue
  • focus an optical microscope on the slide. count total number of cells in the field view and number of cells in a stage of mitosis
  • calculate mitotic index
62
Q

How do you prepare a tempoary root tip mount?

A
  • place root in hydrochloric acid to halt cell division and hydrolyse middle lamella
  • stain root tip with a dye that binds to chromosomes
  • macerate tissue in water using mounted needle
  • use mounted needle at 45 degree angle to press down coverslip and obtain a single layer of cells. avvoid trapping air bubbles.
63
Q

Name 2 dyes that bind to chromosomes.

A
  • toluidine blue (blue)
  • acetic orcein (purple-red)
64
Q

Why is only the root tip used whn calculating a mitotic index?

A
  • meristematic cells at root tip are activley undergoing mitosis
  • cells futher from root tip are elongating rather than dividing
65
Q

Describe the process of binary fission.

A
  • DNA loop replicates . both copies stay attache to the cell membrane. plasmids then replicate in the cytoplasm
  • Cell elongates , seperating the 2 DNA loops
  • cell membane contracts and septum forms
  • cell splits into 2 identical progency cells , each with 1 copy of the DNA loop but a variable number of plasmids.
66
Q

How do viruses replicate?

A
  1. Attachement proteins attach to receptors on host cell membrane.
    - enveloped viruses fuse with cell membrane or move in via endocytosis and release DNA / RNA into cytoplasm or inject it
    - host cell uses viral genetic information to synthesise ne viral proteins /nucleic acid
    - components of new viral particle assemble.
67
Q

What is simple diffusion?

A

the net movement of particles from an area of high to low concentration passivley until equilibrium is reached

68
Q

What are the features of simple diffusion?

A
  • small non-polar molecules involved
  • passive process
  • no carrier protiens involved.
69
Q

What factors affect the rate of diffusion?

A
  • Surface area
  • Temperature
  • Diffusion distance
  • Concentration gradient
70
Q

What is Fick’s law?

A
  • an equation used to determine the rate of diffusion across a cell membrane
  • rate of diffusion = surface area x concentartion gradient / diffusion distance (thickness of memebrane)
71
Q

What is facillitated difussion?

A

facilitated difussion is the passive net movement of large moelcules or ions from an area og high concentration to an area of low concentration via transport proteins until evenly distributed.

72
Q

What are the main features of facilliated diffusion?

A
  • passive pprocess.
  • large and polar moelcules or ions
  • uses transport proteins.

Biology‎ (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions