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Biology Epic Collection > 3.2 Cell Replication > Flashcards

3.2 Cell Replication Flashcards

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1
Q

Describe the structure and function of the cell surface membrane

A
  • phospholipid bilayer with embedded proteins
  • Selectively permeable - enables control of substances passing in and out of the cell
  • Barrier between internal and external environment of cell
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2
Q

Describe the structure and function of the Nucleus

A
  • Nuclear envelope, nuclear pores, nucleolus, DNA/chromatin
  • Controls cell activity through transcription on mRNA
  • Nuclear pores allow substances like mRNA to move between the nucleus and cytoplasm
  • Nucleolus makes ribosomes which are made up of proteins and ribosomal RNA
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3
Q

Describe the structure and function of the Mitochondria

A

Double membrane - inner membrane folded to form cristae
Matrix containing small 70s ribosomes, small circular DNA and enzymes involved in aerobic respiration (glycolysis)
Site of aerobic respiration producing ATP for energy release

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4
Q

Describe the structure and function of the Golgi apparatus

A
  • 3 or more fluid filled membrane bound sacs with vesicles at the edge
  • Receives protein from RER
    modifies/processes protein e.g. adds carbohydrates/sugars
  • Packages into vesicles e.g. for transport to cell surface membrane for exocytosis
  • Also makes lysosomes
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5
Q

Describe the structure and function of the Lysosomes - link to phagocytosis in immunity

A
  • Type of golgi vesicle containing lysosomes - hydrolytic enzymes
  • Release of lysozymes to break down/hydrolyse pathogens or worn out cell components
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6
Q

Describe the structure and function of the Rough Endoplasmic Reticulum

A
  • Float free in cytoplasm or bound to RER. not membrane bound. Made from 1 large and 1 small subunit
  • Site of protein synthesis, specifically translation
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7
Q

Describe the structure and function of the Rough Endoplasmic Reticulum

A

Ribosomes bound by a system of membranes
Folds polypeptides to secondary/tertiary structure
Packages to vesicles, transport to the golgi apparatus

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8
Q

Describe the structure and function of the Rough Endoplasmic Reticulum

A

Ribosomes bound by a system of membranes
Folds polypeptides to secondary/tertiary structure
Packages to vesicles, transport to the golgi apparatus

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9
Q

Describe the structure and function of the Smooth Endoplasmic Reticulum

A

Similar to RER but without ribosomes - system of membranes
Synthesises and processes lipids

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10
Q

Describe the structure and function of Chloroplasts (plants and algae) - link to photosynthesis

A
  • Thylakoid membranes are stacked up in some parts to form grana, which are linked by lamellae. - - These sit in the stroma and are surrounded by a double membrane. Also contains starch granules and circular DNA
  • Chlorophyll absorbs light for photosynthesis to produce organic substances
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11
Q

Describe the structure and function of the cell wall (plants, algae, fungi) - link to structure and function of cellulose

A

Made of cellulose in plants and algae, and of chitin in fungi
Rigid structure surrounding cells in plants, algae, and fungi. Prevents the cell changing shape and bursting (lysis)

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12
Q

Describe the structure and function of the cell vacuole (plants)

A

Contains cell sap - a weak solution of sugars and salts. Surrounding membrane is called the tonoplast
Maintains pressure in the cell to help prevent wilting
Stores unwanted chemicals in the cell

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13
Q

Explain how epithelial cells in the small intestine are specialised for efficient absorption

A
  • Villi and microvilli increase surface area
  • Lots of mitochondria to provide energy for processes like active transport
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14
Q

Differences between prokaryotic and eukaryotic

A

-Prokaryotic has no membrane bound organelles, while eukaryotic has it
-Prokaryotic has no nucleus
-Prokaryotic DNA is circular; Eukaryotic DNA is linear
-Prokaryotic cell wall contains murein while eukaryotic is made of cellulose
-Prokaryotic has 70s ribosomes; eukaryotic has 80s
-Prokaryotic has a capsule; Eukaryotic does not

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15
Q

Explain why viruses are non living

A

Acellular - not made of/able to divide into cells

Non living - unable to reproduce without a host cell

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16
Q

Optical microscopes

A

-Light microscopes have a poor resolution due to the long wavelength of light
-Small organelles in a cell are not visible, but they can see large samples

17
Q

Electron microscopes

A

Electrons are absorbed by air, which is why samples must be in a vacuum. Therefore, dead samples can be examined. The image remains black and white although the samples are stained

18
Q

Transmission microscope process

A

Very thin specimens are stained and placed in a vacuum. An electron gun produces a beam of electrons that pass through the specimen. Some parts absorb the electrons and appear dark. The image produced is 2D and shows detailed images of the internal structure of cells

19
Q

Scanning electron microscope

A

The electrons are beamed onto the surface and the electrons are scattered in different ways depending on the contours on the surface. This produces a 3D image.

20
Q

what is magnification and resolution

A

Magnification - how much bigger the image of a sample is compared to the real size
M=I/A

Resolution - how much distance it takes to distinguish 2 points as separate objects

21
Q

Explain how you would use cell fractionation and ultracentrifugation to separate cell components

A
  1. Homogenise tissue using a blender
    - Disrupts cell membrane / break open cell
    - Release contents / organelles
  2. Place in a cold, isotonic, buffered solution
    - Cold reduces enzyme activity so organelles aren’t broken down
    - Isotonic so water doesn’t move in/out of organelles by osmosis so they don’t burst / shrivel
    - Buffered keeps pH constant so enzymes don’t denature
  3. Filter homogenate
    - Remove large, unwanted debris e.g. whole cells, connective tissue
  4. Ultracentrifugation
    a) Centrifuge homogenate in a tube at a low speed
    b) Remove pellet of heaviest organelle and spin supernatant at a higher speed
    c) Repeated at higher and higher speeds until organelles separated out, each time pellet is made of lighterorganelles
    d) Separated in order of mass/density: nuclei → chloroplasts → mitochondria → lysosomes →endoplasmic reticulum → ribosomes
22
Q

What happens during interphase of the cell cycle

A

S phase - DNA replicates semi conservatively leading to 2 sister chromatids

G1 and G2 - Number of organelles and volume of cytoplasm increases; protein synthesis; ATP content increased

23
Q

describe mitosis

A

Prophase
-Chromosomes condense
-Nuclear envelope breaks down and centrioles move to opposite poles, forming spindle network

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

Anaphase
-Spindle fibres contract, pulling sister chromatids to opposite poles of the cell
-Centromere divides

Telophase
-Chromosomes uncoil
-Nuclear envelope reforms = two nuclei
-Spindle fibres and centrioles break down

Cytokinesis
-The division of the cytoplasm, usually occurs, producing 2 new cells

24
Q

Importance of mitosis in the life of an organism

A

Repairing damages tissues or replacing cells

Asexual reproduction

25
Q

How does prokaryotic cells replicate

A

Binary fission:
1) Circular DNA and plasmids replicate
2) Cytoplasm expands as each DNA molecule moves to opposite poles of the cell
3) Cytoplasm divides
4) 2 daughter cells. Each with a single copy of DNA and a variable number of plasmids

26
Q

Describe what is meant by the fluid mosaic model

A

Molecules within membrane can move laterally

Mixture of phospholipids, proteins glycoproteins and glycolipids

27
Q

Structure of cell membrane

A

Phospholipid bilayer
Phosphate heads are hydrophilic and so are attracted to water. Tails are hydrophobic and repel water
Embedded proteins
Channel and carrier proteins
Glycolipids and glycoproteins
Cholesterol

28
Q

Importance of mitosis in the life of an organism

A

Parent cell divides to produce 2 genetically identical daughter cells for:
- Repairing damaged tissues/replacing cells
- Asexual reproduction

29
Q

How does cancer treatement control cell division

A

Biology Epic Collection (2 decks)

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