Brainscape's Knowledge GenomeTM

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


See full index

Cell biology > Lecture 3&4 - Structure of Eukaryotic Cells > Flashcards

Lecture 3&4 - Structure of Eukaryotic Cells Flashcards

1
Q

What is the difference between Eukaryotic cells and prokaryotes [4]

A
  1. Larger and more complex
  2. Can be unicellular as part of multicellular organisms
  3. Have linear DNA packed as chromosomes in nucleus
  4. Membrane bound organelles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some of the features of UNICELLULAR Eukaryotes

A
  1. Some of the most complex eukaryotic cells
  2. Must perform ALL functions
  3. Some exist as unicellular when food supplies available but aggregate and specialise to form primitive multicellular organisms when food is scarces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the cell membrane of Eukaryotic cells composed of

A

Phospholipids and proteins and due to the amphipathic nature of phospholipids these molecules spontaneously assemble to form closed bilayers

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

What does it mean by two faces.

A

Two faces of the cell membrane are asymmetric in terms of lipid and protein compositions.

In simple terms there are two parts where there’s hydrophobic head and hydrophilic tail.

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

What is the function of the cell membrane?

A
  1. Regulates transport of nutrients into cells and waste materials out
  2. Maintains a balance of chemical conditions in cell i.e pH [homeostasis]
  3. Provides a site for chemical reactions not likely to occur in an aqueous environment
  4. Signal detections in extracellular environment
  5. Interacts with other cells or extracellular matrix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the organelles in a Eukaryote

A
  1. Nucleus
  2. Endoplasmic Reticulum
  3. Ribosomes.
  4. Mitochondria
  5. Golgi apparatus (Golgi complex)
  6. Lysosomes
  7. Peroxisome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the structure and function of the nucleus

A
  1. Membrane bound structure - can see via light ms
  2. Nuclear envelope which contains pores. Inner membrane with nucleus content and outer membrane is linked to rough er
  3. Contains the nucleolus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the nucleolus

A

dark dense revision viable within nucleus by EM

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

Describe the structure and function of the endoplasmic reticulum

A
  1. Extensive membrane structure forming interconnected sacs and tubules
  2. Rough and Smooth
  3. Responsible for lipid synthesis, membrane protein synthesis, Ca2+ ion storage, detoxification
  4. Key features include a network of interconnected closed membrane tubules and vesicles composed of smooth and rough regions.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Properties of the Rough ER

A

attached to ribosomes

synthesises membrane-bound and secreted proteins

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

Properties of Smooth ER

A

Carries no ribosomes

role in producing lipids e.g. membrane lipids and steroid hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the structure and function of ribosomes

A
  1. Complex multi-subunit structures comprise of 50% protein and 50% rRNA
  2. rRNA is key to structure and function of ribosomes
  3. Involved in protein synthesis
  4. Eukaryotic ribosomes consists of 40S and 60S subunits assembled give 80S
  5. Often associated with endoplasmic reticulum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the structure and function of mitochondria

A
  1. Typically 0.5-1.0um but can vary in shape from cylindrical to almost spherical
  2. Contains DNA and ribosomes which are smaller than normal eukaryotic type
  3. Self replicating; reproduces by binary fission
  4. Multiple mitochondria per cell 1 to >1000
  5. Site of ATP production via aerobic metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the distinct regions of the Mitochondria

A
  1. Outer membrane
  2. Inter-membrane space
  3. Inner membrane
  4. Matrix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the structure of a mitochondria

A

Cylindrical to almost spherical

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

What is the function of the mitochondria and how is it made

A

A self replicating via binary fission. Site of ATP production via aerobic metabolism, plays an important role in apoptosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is [mtDNA] Mitochondrial DNA?

A
  1. Genes in mtDNA exhibit cytoplasmic inheritance and encode rRNAs, tRNAS and some mitochondrial proteins
  2. Size and coding capacity of mtDNA varies considerably in different organisms
  3. Products of mitochondrial genes are not exported
  4. Mutations in mtDNA causes several genetic diseases in humans e.g. Leigh Syndrome, Leber Hereditary, optic neuropathy
18
Q

What option to women with mtDNA disease have to have children without passing on the disease?

A
  1. Nucleus from mother’s egg with damaged or abnormal mitochondria is implanted into donor egg.
  2. Donor egg (with nucleus previously removed and destroyed) has normal mitochondria
  3. Egg fertilised by father’s cell.
19
Q

What is the Golgi apparatus?

A
  1. Sac of membrane bound flattened stacks
  2. Sacs form from parts of rough ER which break off and fuse
  3. Inner face close to nucleus
  4. Outer face is thick like plasma membrane
  5. Ensures that vesicles budding off outerface can fuse with plasma membrane
  6. Packages lysosomal proteins and proteins to be secreted from the cell
    Modifies and sorts most ER products
20
Q

What are the distinct regions of the Golgi

A

Cis [ entry]
Medial
trans [exit]
each region contains different sets of modifying enzymes

21
Q

What are lysosomes

A

Single membrane bound organelles containing hydrolytic enzymes

  1. appear electron dense by electron micro
  2. degraded materials taken up by endocytosis
  3. interior pH is low 3.5-5.0
  4. enzymes could cause serious cell damage but cannot function at neutral cytoplasmic pH
  5. not present in plant cells - instead plants have vacuoles
22
Q

what is endocytosis

A

taking of material through invagination and cell debris

23
Q

What happens if the lysosomal enzyme is missing due to genetic defect?

A

accumulation of material: lysosomal storage disease - usually fatal in adolescence

24
Q

What are Peroxisomes?

A

small organelle present in the cytoplasm of many cells which contain the reducing enzyme catalase and usually some oxidase

  1. single membrane-bound organelles
  2. can be diverse in size and enzyme composition
  3. contain catalase and grate oxidase
  4. breaks down very Long chain fatty acids via beta oxidation
  5. oxidation of toxins (including alcohol)
25
Q

What are components of the cytoskeletons?

A
  1. Cytosol
  2. Microfilaments
  3. Actin and Myosin
  4. Microtubules
26
Q

What is the cytosol?

A
  1. Portion of the cell enclosed by the plasma membrane but not part of any organelles
  2. Not static, contents within the cell are constantly moving
27
Q

What is the cytoskeleton?

A
  1. Lattice-like array of filaments of fine tubules
  2. involved in cell movement, cell division, maintenance of cell shape, intracellular trafficking of organelles, cordiating movement of tissues
28
Q

What are microfilaments

A

Component of the cytoskeleton

role: cytokinesis, amoeboid movement, cell motility, changes in cell shape, endocytosis and exocytosis, cell contractility and mechanical stability

interacts with other filaments and “motor” to create movements: contraction can cause shape change

29
Q

What are Actin and myosin

A
  1. Actin filaments work with myosin in muscle fibers
  2. Myosin filaments walk along the tethered actin hence pulling the filaments towards the centre to cause muscle contraction
30
Q

What are microtubules?

A
  1. Tubues of tubules: grow by polymerisation
  2. Can form “trackways: in cells along which motor proteins (e.g. kinesics) drag vesicles, organelles etc
  3. Fundamental role in partitioning of chromatids in cell division.

role: help support and give shape to cells

31
Q

What is polymerisation

A
  1. Process in which the small monomer units join together to form a large polymer molecules, from specific microtubules organelles organising centres
  2. Can form Trackways in cells along which motor proteins (e.g.kinesics) drag vesicles, organelles etc
  3. Fundamental role in partitioning of chromatids in cell division
32
Q

What are Chromatids?

A

One of two strands of newly copied chromatid. If two are joined together at the centromere they are called sister chromatids and are genetically identical

33
Q

What are intermediate filaments?

A
  1. Structure about 10nm in diameter
  2. Many different types that differ in composition and function
  3. May have a role in maintaining cell shape, tissue and integrity.
34
Q

What are the organelles of a plant cell?

A

Chloroplasts, vacuoles, specialised peroxisomes.

35
Q

What is the structure of a plant cell?

A

Plasma membrane surrounded by rigid cell wall. Plant cells communicate via special connection in the cell wall.

36
Q

What is a Vacuole

A

Stores water ions and nutrients and degrade macromolecules (similar to lysosomes)

  • may occupy up to 80% of plant cell
  • Inflow of water by osmosis causes vacuole expansion and maintenance of turgor pressure
  • Expansion of vacuole involved in cell elongation
37
Q

What are chloroplasts?

A
  • Found in photosynthetic plant cells
  • Captures light to produce ATP during photosynthesis
  • Contain free pigment chlorophyll and other pigments that absorb light and generate NADPH and ATP during photosynthesis - used to produce organic molecules
  • Double membrane and contains its own DNA
  • Thylakoid membrane fused into stacks called grant.
38
Q

What are specialised peroxisomes?

A

One type is found in leaves where it is involved in photorespiration. Glyoxysomes are found in germinating seeds - carry out alyoxylate cycle to convert fatty acids into sugar

39
Q

What is photorespiration?

A

utilises oxygen and generates carbon dioxide

40
Q

What is the plasmodesmata?

A

Directly connects the cytosol to adjacent cells in higher plants and allows communication between them

Cell biology (6 decks)

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