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Bio > Cell Structure, Mitosis & Binary Fission > Flashcards

Cell Structure, Mitosis & Binary Fission Flashcards

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Biology 101 flashcards
1
Q

DNA in eukaryotes

A
  • DNA enclosed in nucleus
  • long + linear
  • Attached to proteins (histones)
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2
Q

DNA in prokaryotes

A
  • DNA free-floating in cytoplasm (no nucleus)
  • circular
  • not attached to proteins (histones)
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3
Q

What is chromatin?

A

DNA and histone proteins in nucleus during most of cell cycle (no chromosomes yet)

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4
Q

What is a chromatid?

A

One of 2 identical copies of a chromosome held together by a centromere before cell division

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5
Q

What is mitosis?

A
  • Cell replication which produces two genetically identical daughter cells
  • gives genetic stability
  • used for tissue growth, repair, cell replacement, asexual reproduction
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6
Q

What is prophase?

A
  • chromosomes condense
  • centrioles move to opposite sides
  • nuclear membrane breaks down
  • spindle fibres form
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7
Q

What is metaphase?

A
  • chromosomes line up at equator
  • centromere of each chromosome attached to spindle
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8
Q

What is anaphase?

A
  • spindle fibres contract and pull on centromeres
  • centromeres split
  • sister chromatids pulled to opposite poles
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9
Q

What is telophase?

A
  • chromatids reach opposite poles (begin to uncoil - chromosomes)
  • nuclear membranes form
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10
Q

What is interphase?

A
  • longest phase
  • DNA content doubled via replication
  • cell organelles replicated (mitochondria + ATP content increased)
  • increase in protein synthesis
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11
Q

What is cytokinesis?

A
  • follows mitosis
  • splitting of cytoplasm in two
  • two new cells form (cell-surface membrane and, in plants, cellulose cell wall forms)
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12
Q

How is algae different?

A
  • similar to plant cells (carry out photosynthesis, contain same organelles)
  • NOT plant cells (cells undifferentiated and unicellular)
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13
Q

How are fungi different?

A
  • NOT plant cells or animal cells
  • contain cell walls (chitin not cellulose)
  • do not photosynthesise so no chloroplasts
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14
Q

What organelles do prokaryotes sometimes contain?

A
  • slime capsule surrounding cell wall
  • one or more plasmids
  • one or more flagella
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15
Q

Are viruses cells?

A

No they are acellular and non-living

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16
Q

What do viruses not contain?

A

Nucleus, organelles, cell-surface membrane, cytoplasm

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17
Q

What does a typical virus contain?

A

Genetic material, capsid, attachment proteins on outside

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18
Q

Nucleus

A
  • Bound by double membrane
  • nuclear membrane has nuclear pores (communication with cytoplasm)
  • nucleoplasm (granular, jelly-like material)
  • nucleolus (smaller sphere inside, site of rRNA production + makes ribosomes)
  • contains DNA
  • site of DNA replication + transcription (making mRNA)
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19
Q

Ribosomes

A
  • made up of protein + rRNA
  • either in cytoplasm singularly or attached to RER
  • site of protein synthesis
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20
Q

Smooth endoplasmic reticulum

A
  • flattened membrane sacs which form internal transport system
  • lacks ribosomes
  • production + transport of lipids & carbohydrates
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21
Q

Rough endoplasmic reticulum

A
  • flattened membrane sacs which form internal transport system
  • surface has ribosomes (that produce secretory proteins, sent to Golgi)
  • synthesis + transport of proteins
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22
Q

Golgi apparatus and vesicles

A
  • flattened membrane sacs
  • adds carbohydrates to proteins from RER to form glycoproteins
  • packages proteins into Golgi vesicles for secretion
  • produces lysosomes (type of Golgi vesicle that releases lysozymes)
  • abundant in secretory cells e.g. pancreas
23
Q

Lysosomes

A
  • sacs of hydrolytic enzymes (enzymes have to be kept apart from rest of cell or will destroy it)
  • breaks down dead cells, material, digests worn-out organelles
  • formed by Golgi apparatus
24
Q

Mitochondria

A
  • double membrane
  • folds of inner membrane = cristae
  • fluid centre = mitochondrial matrix (contains enzymes for respiration, DNA, ribosomes)
  • loop of mitochondrial dna
  • site of aerobic respiration
25
Q

Chloroplasts

A
  • only found in plant cells + algae
  • flattened biconvex discs surrounded by two membranes
  • membrane system consisting of many flattened sacs = thylakoids
    -> form stacks called grana (provide large surface area for chlorophyll molecules which absorb light for photosynthesis)
  • membrane system surrounded by stroma (contains enzymes, sugars, starch granules)
26
Q

What organelles are found in plant cells but NOT animal cells?

A
  • cell wall
  • chloroplasts
  • vacuole
27
Q

Cell wall

A
  • found in plants and fungi
  • provides structural strength to cell
28
Q

What is a plant cell wall made up of?

A

Cellulose

29
Q

What is a fungi cell wall made up of?

A

Chitin (nitrogen-containing polysaccharide)

30
Q

Cell vacuole

A
  • found in plant cells
    -filled with fluid surrounded by single membrane (tonoplast)
  • makes cells turgid (provides support)
  • temporary store of cell sap (sugars, amino acids, pigment)
31
Q

Cell membrane

A
  • found in all cells
  • phospholipid bilayer
  • controls entrance and exit of molecules
32
Q

How are specialised cells organised?

A

Tissues —> organs —> systems

33
Q

What kinds of cells undergo mitosis?

A

Eukaryotic

34
Q

Do eukaryotes have membrane-bound organelles?

A

Yes

35
Q

Ribosomes in eukaryotes

A

Larger than prokaryotes
80s

36
Q

Cell wall in eukaryotes

A

Does NOT contain murein

37
Q

Do prokaryotes have membrane-bound organelles?

A

No

38
Q

Ribosomes in prokaryotes

A

Smaller than eukaryotes
70s

39
Q

Cell wall in prokaryotes

A

Murein cell wall

40
Q

How do prokaryotes divide?

A

Binary fission

41
Q

What is binary fission?

A

Asexual division in prokaryotes

42
Q

What is stage 1 of binary fission?

A

Cell growth - prepare for division

43
Q

What is stage 2 of binary fission?

A

DNA replication - circular chromosome replicated once, plasmids may be replicated multiple times

44
Q

What is stage 3 of binary fission?

A

Movement of DNA - each replicated circular chromosome moves to opposite poles of cell, plasmids distributed randomly between two poles

45
Q

What is stage 4 of binary fission?

A

Cell wall growth - membrane starts to divide and new cell walls form between 2 DNA molecules

46
Q

What is stage 5 of binary fission?

A

Cytoplasm division - cytoplasm of original cell divided into 2 identical daughter cells

47
Q

How to calculate mitotic index?

A

(Number of cells undergoing mitosis)/(total number of cells) x100

48
Q

How to calculate the number of cells/bacteria in a population

A

Number of cells at beginning x 2^number of divisions

49
Q

Do viruses undergo cell division?

A
  • No
  • they attach to specific host cells using attachment proteins (which are complementary to receptors on host cells£
  • inject nucleic acid
  • host cell produces more viruses (using copies of nucleic acids + proteins)
  • viruses released by lysis of cell
50
Q

What is cancer?

A

uncontrolled cell division leading to a tumour that invades surrounding tissue

51
Q

What is a tumour?

A

An abnormal growth of cells

52
Q

What causes cancer?

A

Mutations in genes that control the speed of cell division

53
Q

What kinds of cancer treatments are there?

A
  • drugs and radiotherapy disrupt cell cycle (can affect normal healthy cells)
54
Q

How are epithelial cells adapted for the absorption of digested food products?

A
  • cell surface membrane folded into microvilli - provides large surface area for absorption
  • numerous mitochondria - provide energy (ATP) for active uptake of digested food molecules

Bio (10 decks)

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