Brainscape's Knowledge GenomeTM

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


See full index

biology paper 1 > cells > Flashcards

cells Flashcards

cells

1
Q

what are the groups of eukaryotic cells?

A

-fungi
-animal
-plants
-protists
(algal and fungal cell are similar to plant cells)

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

what are the distinguishing features of eukaryotic cells?

A
  • cytoplasm containing membrane-bound organelles
  • so DNA enclosed in a nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the structures found in animal cells?

A
  • cell membrane
    -mitochondrion
    -nucleus
    -ribosomes
    -rough endoplasmic reticulum (RER)
    -Smooth endoplasmic reticulum (SER)
    -Golgi apparatus and vesicles
    -lysosomes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the structures found in a plant cell?

A
  • cell membrane
    -mitochondrion
    -nucleus
    -ribosomes
    -rough endoplasmic reticulum (RER)
    -Smooth endoplasmic reticulum (SER)
    -Golgi apparatus and vesicles
    -lysosomes
    -chloroplast
    -cell wall
    -cell vacuole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

diagram of a plant and animal cell with labelled structures

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

describe the structure of the cell surface membrane

A
  • found in all cells phospholipid bilayer embed within and attached on the outside (proteins, carbohydrates and cholesterol)
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
  • selectively permeable so enables control of passage of substance in/out of cell
    -molecules/receptors/antigens on surface allows cell recognition/signalling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe the structure of the nucleus

A

-nuclear envelope: double membrane that surrounds the nucleus - controls entry/exit of materials
-nuclear pores: allow passage of larger molecules
-nucleoplasm: granular, jelly like material that makes up the bulk of the nucleus
-nucleolus(dense region): site of rRNA production and makes ribosomes
-chromosomes(highly condensed)/ chromatin (condensed) : consists of protein/histone-bound, linear DNA

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

describe the function of a nucleus

A
  • holds/stores genetic information which codes for polypeptide (proteins) in the form of DNA and chromosomes
    -site of DNA replication
  • site of transcription (part of protein synthesis) producing mRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe the structure of ribosomes

A

-not a membrane bound organelle
-made of ribosomal RNA and protein ( two subunits)- 80s found in eukaryotic cells, 70s found in prokaryotic cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

describe the function of a ribosome

A
  • site of protein synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe the structure of rER and sER

A

-both have folded membranes called cisternae
-rER has ribosomes on cisternae (outer membrane)
-sER lacks ribosomes on surface, more tubular in appearance
- single membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe the function of rER + sER

A

rER:
● Ribosomes on surface synthesise proteins
● Proteins processed / folded / transported inside rER
● Proteins packaged into vesicles for transport e.g.. to Golgi apparatus
sER:
● Synthesises and stores lipids and carbs
● E.g.. cholesterol and steroid hormones

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

describe the structure of Golgi apparatus and Golgi vesicles

A

-Golgi apparatus: flattened membrane sacs, has a single membrane
- Golgi vesicles: small membrane sac

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

describe the function of Golgi apparatus and Golgi vesicles

A

Golgi apparatus:
-modifies protein, e.g. adds carbohydrates to produce glycoproteins
- modifies lipids, e.g. adds carbohydrates to make glycolipids
- packages proteins/ lipids into Golgi vesicles
-produces lysosomes (a type of Golgi vesicles)

Golgi vesicles:
-transports proteins/lipids to their required destination
- e.g. moves to and fuses with cell-surface membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe the structure of lysosomes

A
  • bags of digestive enzymes
  • has hydrolytic enzymes
  • single membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe the function of lysosomes

A

-release hydrolytic enzymes (lysozymes) to hydrolyse pathogens or worn out cell components (organelles) for reuse of materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

describe the structure of mitochondria

A
  • double membrane that controls the entry/exit of material
  • inner membrane is folded to form extension of cristae
  • matrix: contains small ribosomes(70s) and circular DNA which allows the mitochondria to control the production of their own proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe the function of mitochondria

A
  • site of aerobic respiration
  • to produce ATP for energy release (energy carrier molecule)
    -e.g. for protein synthesis/vesicle movement/active transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

describe the structure of chloroplasts in plants and algae

A
  • chloroplast envelope: double plasma membrane that surrounds the organelle- highly selective in what can be entered/exit the chloroplast
    -grana: stacks of thylakoid(folded membrane embedded with pigments and is the 1st stage of photosynthesis)
    -lamella: thylakoids linking grana
    -stroma: fluid filled matrix where the 2nd stage of photosynthesis takes place. contains thylakoid membranes, small 70s ribosomes, circular DNA and within the stroma are a number of other structures e.g. starch granules and lipid droplets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

describe the function of chloroplasts in plants and algae

A
  • absorbs light energy for photosynthesis to produce organic substances e.g. carbohydrates/lipids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

describe the structure of the cell wall in plants, algae and fungi

A
  • composed mainly of cellulose ( a polysaccharide) in plants/algae
  • composed of chitin ( a nitrogen-containing polysaccharide) in fungi
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

describe the function of the cell wall in plants, algae and fungi

A
  • provides mechanical strength to cells
  • so prevents cell changing shape or bursting under pressure due to osmosis
24
Q

describe the structure of the cell vacuole in plants

A

a large shaped organelle that varies in shape containing cell sap
- single membrane

25
Q

describe the function of the cell vacuole in plants

A
  • maintains turgor pressure in cell (stopping plant wilting)
  • contains cell sap - stores sugars, amino acids, pigments and any waste chemicals
26
Q

describe how eukaryotic cells are organised in complex multicellular organisms

A

in multicellular organisms, eukaryotic cells become specialised for specific functions
- tissue: group of specialised cells with a similar structure working together to perform a specific function, often with the same origin
- organ: aggregations of tissues performing specific functions
- organ system: group of organs working together to perform specific functions

27
Q

what are the distinguishing features of prokaryotic cells? and examples

A
  • cytoplasm lacking membrane-bound organelles
    -so genetic material not enclosed in a nucleus
  • prokaryotic organisms e.g. bacteria and archaea (always unicellular)
28
Q

what are the structures that are sometimes present in a prokaryotic cell?

A
  • capsule: additional protection, slimy layer made out of proteins which prevents cell from desiccating (drying out)
  • plasmids: small rings of DNA
    -flagella: rotates to enable the bacteria to move
29
Q

what are the structures that are always present in a prokaryotic cell?

A
  • cell surface membrane
  • cell wall: contains murein, a glycoprotein
  • cytoplasm
  • small 70s ribosomes
  • circular DNA: free in cytoplasm, not associated with proteins
30
Q

compare and contrast the structure of eukaryotic and prokaryotic cells

A
  1. eukaryotic has membrane bound organelles e.g. mitochondria, ER but in prokaryotic there’s no membrane bound organelles e.g. no mitochondria and ER
  2. eukaryotic has a nucleus containing DNA but the DNA in prokaryotic is free in the cytoplasm instead
  3. eukaryotic: DNA is long and linear and associated with histone proteins
    prokaryotic: DNA is short and circular and isn’t associated with proteins
  4. eukaryotic has larger 80s ribosomes in cytoplasm. prokaryotic has smaller 70s ribosomes
  5. eukaryotic: cell walls only in plant, fungi and algae containing chitin or cellulose.
    prokaryotic: all cells have cell walls containing murein, a glycoprotein
  6. eukaryotic: plasmids/ capsules are never present (sometimes flagella)
    prokaryotic: plasmids, flagella and capsules are sometimes present
  7. eukaryotic: larger overall size
    prokaryotic: smaller in overall size
31
Q

describe why viruses are described as acellular and non-living

A
  1. acellular: not made of cells, no cell membrane/ cytoplasm/organelles
  2. non-living: have no metabolism, cannot independently move/respire/replicate/ excrete
32
Q

describe the general structure of a virus particle

A

-nucleic acids surrounded by a capsid (protein coat)
- attachment proteins allow attachment to specific host cells
- no cytoplasm, ribosomes, cell wall, cell surface membrane etc.
- some also surrounded by a lipid envelope e.g. HIV ( not all viruses have a lipid envelope but HIVs do)

33
Q

what’s the difference between bacterial capsules and virus capsids?

A
  • bacterial (‘slime’) capsules provide protection and help with adhesion
  • virus capsid (‘protein coat’) protect genetic material
34
Q

how does prokaryotic cells make ATP?

A

has no membrane bound organelles so doesn’t have mitochondria but will still perform respiration to make ATP

35
Q

what is cell fractionation used for?

A

-cells are broken open to release the contents and organelles are then separated
-used to isolate different organelles so they can be studied. This enables individual organelle structures and functions to be studied
-before cell fractionation can begin, the tissue is placed in a cold, buffered, isotonic solution
-there are 2 stages: homogenisation and ultracentrifugation

36
Q

what happens in stage 1 of cell fractionation: homogenisation?

A

1.homogenise tissue/use a blender: disrupts the cell membrane, breaking open cells to release contents/organelles
2.placed in a cold, isotonic, buffered solution:
-cold: reduce enzyme activity so organelles not broken down/damaged
-isotonic: water doesn’t move in or out of organelles by osmosis so they don’t burst
- buffered: to keep pH constant so enzyme doesn’t denature
3. filter homogenate: remove large, unwanted debris e.g. whole cells, connective tissue

37
Q

what happens in stage 2 of cell fractionation: ultracentrifugation

A

ultracentrifugation: separates organelles in order of density/mass
- centrifuge homogenate in a tube at a low speed
-remove pellet or heaviest organelle and respin supernatant at a higher speed
-repeat at increasing speeds until separated out, each time the pellet is made of lighter organelles (nuclei → chloroplast/mitochondria→ lysosomes → ER → ribosomes

38
Q

what is the summarised stages of the cell cycle in the eukaryotic cell?

A

Stage 1:Interphase
-cell grows and organelles are synthesised
-DNA replicates semi-conservatively (S phase)
-Leading to 2 chromatids (identical copies) joined at a centromere
-chromosomes are not visible
-Number of organelles & volume of cytoplasm increases, protein synthesis (G1 / G2)
Stage 2: Mitosis
-Nucleus divides
-To produce 2 nuclei with identical copies of DNA produced by parent cell
Stage 3: Cytokinesis
-Cytoplasm and cell membrane (normally) divide
-To form 2 new genetically identical daughter cells

39
Q

what happens in stage 1 of prophase?

A
  • Nuclear envelope breaks down
    -Chromosomes condense, becoming shorter / thicker so visible
    ○ Appear as 2 sister chromatids joined by a centromere
  • Centrioles move to opposite poles forming spindle network
40
Q

what happens in stage 2 of metaphase?

A

-Spindle fibres attach to chromosomes by their centromeres
-Chromosomes align along equator

41
Q

what happens in stage 3 of anaphase?

A
  • Spindle fibres shorten / contract
  • Centromere divides
  • Pulling chromatids (from each pair) to opposite poles of cell
42
Q

what happens in stage 4 of telophase?

A
  • Chromosomes uncoil, becoming longer / thinner and are no longer visible
  • Nuclear envelopes reform = 2 nuclei
    -chromatids have reached opposite poles
  • Spindle fibres / centrioles break down
43
Q

diagram of the different stage of cell cycle

A
44
Q

why do some eukaryotic cells not undergo the cell cycle?

A

-within multicellular organisms, not all cells retain the ability to divide (e.g. neurons)
-Only cells that do retain this ability go through a cell cycle

45
Q

Explain the importance of mitosis in the life of an organism

A

Parent cell divides to produce 2 genetically identical daughter cells for:
● Growth of multicellular organisms by increasing cell number
● Replacing cells to repair damaged tissues
● Asexual reproduction

46
Q

Describe how tumours and cancers form

A

Mitosis is a controlled process so:
● Mutations in DNA / genes controlling mitosis can lead to uncontrolled cell division
● Tumour formed if this results in mass of abnormal cells
○ Malignant tumour = cancerous, can spread (metastasis)
○ Benign tumour = non-cancerous

47
Q

Suggest how cancer treatments control rate of cell division

A

-Some disrupt spindle fibre activity / formation
○ So chromosomes can’t attach to spindle by their centromere
○ So chromatids can’t be separated to opposite poles (no anaphase)
○ So prevents / slows mitosis
-Some prevent DNA replication during interphase
○ So can’t make 2 copies of each chromosome (chromatids)
○ So prevents / slows mitosis

48
Q

Describe how prokaryotic cells replicate

A

Binary fission:
1. Replication of circular DNA
2. Replication of plasmids
3. Division of cytoplasm to produce 2 daughter cells
○ Single copy of circular DNA
○ Variable number of copies of plasmids

49
Q

Describe how viruses replicate

A

Being non-living, viruses do not undergo cell division
1. Attachment proteins attach to complementary receptors on host cell
2. Inject viral nucleic acid (DNA/RNA) into host cell
3. Infected host cell replicates virus particles:
a. Nucleic acid replicated
b. Cell produces viral protein / capsid / enzymes
c. Virus assembled then released

50
Q

true or false: mitosis repairs cells?

A

mitosis creates new cells to replace damaged or dead ones, therefore
repairing the tissue, but not the cells themselves.

51
Q

when does DNA replication occur?

A

in the interphase which is before mitosis

52
Q

what are chromatids?

A

A chromatid is one of the two identical halves of a chromosome that
has been replicated. These are held together by a centromere.

53
Q

what’s the difference between centromeres and centrioles?

A

Centromeres join sister chromatids, while centrioles are organelles
involved in spindle formation.

54
Q

true or false: “Cytokinesis always happens.”

A

Some cells (eg. muscle cells) undergo mitosis (nuclear division) without
cytokinesis (cytoplasmic division), so have multiple nuclei.

55
Q

true or false: “In binary fission in prokaryotic cells,
bacterial chromosomes replicate.”

A

Chromosomes consist of linear DNA associated with histones and are
only found in eukaryotic cells. Bacteria have circular DNA (no histones).

biology paper 1 (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions