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Biology- Sac 1 > Summary > Flashcards

Summary Flashcards

1
Q

Cell membrane 1

A

The plasma membrane is a selectively permeable barrier between the intracellular and the extracellular environment. It is made of a phospholipid bilayer which is studded with many molecules.

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2
Q

ribosomes

A

Ribosomes are tiny structures made of ribosomal RNA (rRNA) and proteins that fold into a large and small subunit. Ribosomes assemble the building blocks to make proteins.

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3
Q

cytoskeleton

A

A large network of protein filaments that start at the nucleus and reach out to the plasma membrane. The cytoskeleton is critical for maintaining shape and transporting vesicles around the cell.

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4
Q

cell wall

A

A sturdy border outside the plasma membrane that provides strength and structure to plant, bacterial, and fungal cells.

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5
Q

vesicle

A

A small, membrane-bound sac that transports substances into or out of a cell, or stores substances within a cell.

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6
Q

vacuoles

A

A membrane-bound sac that is used for water and solute storage. Vacuoles can also play a role in maintaining plant cell structure.

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7
Q

chloroplasts

A

A double membrane-bound organelle that contains flattened, fluid-filled sacs that are the site of photosynthesis. Chloroplasts also contain their own DNA and ribosomes

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8
Q

lysosomes

A

A membrane-bound vesicle that contains digestive enzymes. It is responsible for breaking down cell waste and toxins, acting like a garbage disposal.

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9
Q

Golgi apparatus

A

Stacked flattened sacs that are the sites of protein sorting, packaging, and modification for use in the cell or export. Protein-filled vesicles often fuse with or bud off from the Golgi apparatus. Also known as the Golgi body.

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10
Q

Smooth endoplasmic
reticulum

A

A membranous chain of connected and flattened sacs which are not coated with ribosomes. The smooth endoplasmic reticulum is responsible for the production of lipids in a cell.

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11
Q

Rough Endoplasmic Reticulum

A

A membranous chain of connected and flattened sacs which are coated with ribosomes. This allows the rough endoplasmic reticulum to synthesize and modify proteins. The rough endoplasmic reticulum typically surrounds, or is close to, the nucleus

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12
Q

Mitochondria

A

Contains a double membrane
Mitochondria are the site of aerobic cellular
respiration, a chemical reaction that produces the ATP required to power cellular processes. They also contain their own DNA and ribosomes.

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13
Q

nucleus

A

The nucleus is surrounded by a double membrane. Its role is to protect and confine the genetic information (DNA) of the cell. Inside the nucleus is a smaller structure known as the nucleolus which is the site of ribosome production

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14
Q

cytosol

A

a fluid found inside every living cell that consists of water containing dissolved substances

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15
Q

Eukaryotic cell

A

-unicellular and multicellular
-contains membrane bound organelles
- contain a nucleus and DNA in multi linear chromosomes
-divide through mitosis and meiosis.
-plant, animal, fungi and protists

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16
Q

prokaryotic cell

A
  • a unicellular organism
    -no membrane bound organelles
    -no nucleus
    -contain DNA in a circular chromosome
    -divide with binary fission
    -bacteria
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17
Q

Cell Membrane 2

A

all living cells have a plasma membrane.

It is thin, selectively-permeable that controls the exchange of materials, receives hormone messages and separates the cell from its surroundings

made up of a phospholipid bi-layer

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18
Q

Fluid-Mosaic Model

A

The plasma membrane is fluid as it continuously moves from side to side.

this mosaic (made up of different components) comes from proteins and carbohydrates embedded in the membrane.

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19
Q

Polar

A

when molecule is not charged overall but parts are slightly positive and other parts are slightly negative

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20
Q

Non-Polar

A

When a molecule is not charged because all the positive and negative charges are distributed evenly

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21
Q

charged

A

when a molecule is overall negative or positive

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22
Q

Hydrophobic

A

a molecule that is repelled by water

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23
Q

Hydrophilic

A

A molecule that is attracted to water

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24
Q

Lipids

A

example- phospholipid

chemical properties- usually uncharged/non-polar

usually hyrdophobic

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25
Carbohydrates
Example- glucose chemical properties- are polar in their singular form. but can become difficult to dissolve if they form polymers like cellulose hydrophilic as monomer
26
Proteins
Example- Enzymes Chemical Properties- proteins vary in properties. can be uncharged/ non-polar or polar and have charged groups depend on the protein
27
Nucleic acid
example- DNA Chemical Properties- negatively charged hydrophilic
28
Phospholipids
Consist of a polar head and a non-polar tail. Fatty acid tail and phosphate head.
29
Crossing the membrane
Hydrophobic particles can dissolve in the membrane and easily diffuse across it Hydrophilic substances are unable to dissolve in the membrane
30
Proteins- membrane
various proteins are found in the cell membrane. some are permanently fixed to the membrane (integral) while other are only temporary (peripheral) some of the membrane proteins span the width of the membrane (transmembrane). some are only on the inner layer and some on the outer layer.
31
channel protein
most of the membrane have non-polar tails. uncharged molecules can move through unaided. they are tunnels that allow selected substances to pass through them from one side of the membrane to the other some are open all the time and some have gates that block the flow unless triggered. substances pass through by diffusion and require no energy
32
carrier proteins
bind to molecules or ions on one side of the membrane, change shape and release the molecules or ions on the others side of the membrane carry against the concentration gradient. requires energy and called active transport.
33
Glycoproteins and Glycolipids
are lipids or proteins with a chain of sugars attached that protrudes into the external surroundings Glycoproteins play a role in cell recognition and signaling. they have receptors. hormones or neurotransmitters bind to them, triggering a series of chemical reactions within the cell. glycolipids provide energy and also play a role in cell-to cell recognition.
34
Cholesterol
scattered in the lipid bilayer. maintain a stable membrane fluidity. keeps phospholipid bound at higher temperatures disrupts the fatty acid tails, stopping phospholipids form becoming sold in cold temperatures.
35
Passive- Diffusion
the net movement of particles across a membrane to a region of lower solute concentration (along solute concentration gradient) requiring no energy
36
passive- facilitated diffusion
the net movement of particles across a membrane to a region of lower solute concentration (along solute concentration gradient) requiring the assistance of transmembrane proteins requiring no energy
37
Passive- osmosis
the net movement of water across a membrane to a region of higher solute concentration requiring no energy
38
Active- active transport
the net movement of particles across a membrane to a region of higher solute concentration (against the solute concentration gradient) requiring energy (ATP) and the assistance of a protein carrier
39
Active- endocytosis
a process of cellular ingestion involving the plasma membrane folding inward to bring substances into the cells inside a vesicle
40
Active- Exocystosis
a process of cellular secretion or excretion involving substances contained in vesicles being discharged from the cell by fusion of the vesicle membrane with the plasma membrane.
41
cell replication
the process where a parent cell divides to produce two genetically identical daughter cells.
42
why do they divide
-growth and development -maintenance and repair -reproduction
43
Binary fission- step 1
a prokaryotic cell before cell replication -circular DNA and plasmid must be replicated
44
Binary fission- step 2
the circular chromosomes is uncoiled and the DNA is replicated. Plasmid also replicated
45
Binary fission- step 3
the cell elongates as it prepares to separate into two new cells and the duplicated circular chromosomes migrate to opposite ends
46
Binary fission- step 4
begins to undergo cytokinesis- the process of separating into two new cells- by pinching inwards and creating a septum. Because plasmids replicated independently of the circular chromones, these will not always be evenly distributed between the two new cells.
47
Binary fission- step 5
A new cell wall and membrane are formed down the Centre of the cell
48
Binary fission- step 6
two new genetically identical cells are formed
49
main phases
interphase- longest phases, the cell doubles its mass and duplicated its components mitosis- the nucleus divides cytokinesis- the cytoplasm divides
50
Interphase
-first phases, begins after the end of cell division -made up of three phases G1, S and G2. G0 can also be a part of it after G1
51
G1
- first growth phase -after cell division the cell is small so it grows back to its original size -more organelles are produced
52
G0
cells will no longer divide but continue to perform their normal functions. e.g. neurons, nerve or hear muscle cells
53
S
-synthesis phase - cell duplicated its DNA (linear) to make two sister chromatids
54
G2
-second growth phase -cell continues to grow and undergo metabolic activity - the cell prepares cell division - all the DNA is proofread to ensure no mistakes during Synthesis.
55
Checkpoints
G1- verifies that the cell has grown properly, has enough resources to continue and DNA has not been damaged G2- ensures that DNA has replicated properly and the cell has enough resources more mitosis Metaphase: In mitosis and checks formation of the spindle fibers. incorrect formation can lead to chromosome malfunctions.
56
Mitosis sub phases
Prophase, metaphase, Anaphase, Telophase
57
Prophase
- chromosome condenses and becomes visible -centrosomes move towards the opposite sides of the cells (the poles) -spindle fibers begin to form -nuclear membrane disappears
58
Metaphase
-spindle fibers attach to chromones at centromeres -chromones align at the equator between the poles
59
Anaphase
-the spindle fibers contract until the centromeres split, separating the sister chromatids -the separated chromatids, now separate chromosomes are pulled towards the opposite poles by the spindle fibers.
60
Telophase
-nuclear membranes reform around the two sets of chromosomes -the spindle fibres disappear -the chromosomes decondense to become long thin chromatin fibres again.
61
Cytokinesis
can sometimes overlap with telophase division of the cytoplasm
62
Cytokinesis in animal cells
-cytoplasm pinches in as a ring of contractile proteins squeezes the centre of the cell. called cleavage furrow -two daughter cells are pinched apart
63
cytokinesis in plant cells
- a new plasma membrane and cell wall forms between the two cells -this growth, called the cell plate begins int eh center of the cell, and grows until it fully separates the two daughter cells.
64
two ways cells can die
Apoptosis and Necrosis
65
Necrosis
- bad - occurs when a cell is damaged by an external force, such as poison or injury - triggers an inflammatory response that can damage nearby cells.
66
Apoptsis
-good -occurs when the cell receives an internal signal to self-destruct -does not trigger an inflammatory repones.
67
apoptosis initiation (way in which cells initiates apoptosis)
-mitochondrial pathway -death receptor pathway
68
mitochondrial pathway
apoptosis triggerd by internal signals from the mitochondrial which releases cytochrome C
69
Death Receptor Pathway
apoptosis triggered by external signals from immune system
70
apoptosis process
once activated by either pathway, caspase enzymes become activated, resulting in the destruction of the cell such as: -digestion of cell proteins, organelles and DNA -membrane blebbing and breakage: as the cytoskeleton is digested, the structural integrity of the cell is weakened.
71
Apoptosis clean up
signals are sent to phagocytes to destroy the apoptosis bodies. -cell shrinks, chromatin condenses -budding -apoptosis bodies are phagozytosed (an eating cell)
72
necrosis clean up
- cell swells -cell becomes leaky, blebbing (holes form in the membrane) -cellular and nuclear lysis causes inflammation.
73
Apoptosis dot point
- caused by body -beneficial to organism -series of biochemical steps leading to cell destruction -can help to prevent diseases such as tumors -shrinking of cytoplasm, condensation of nucleus, fragmenting of DNA -blebbing of plasma membrane without loss of integrity -energy dependent
74
necrosis dot point
-caused by external factors such as infection -harmful to organism premature death of cells and living tissue -can cause diseases such as chronic inflammation -swelling of cytoplasm and mitochondria -loss of membrane integrity -no energy required.
75
apoptosis function
a natural and essential process for healthy functioning, eliminating DNA-damaged, superfluous, or unwanted cells
76
apoptosis malfunction
-regulation of apoptosis can sometimes go wrong, causing a number of health issues -sometimes the wrong cells self destruct -sometimes the ones that should be destroyed remain intact.
77
excessive apoptosis
-may result in the loss of vital tissues -excessive number of neurons is called neurodegeneration. Alzheimer's is a disease caused by an excessive number of apoptosis of brain cells
78
decreased apoptosis
-mutations in specific genes can cause the cell cycle to be disrupted and apoptosis to not occur -can cause unregulated cell division and abnormal growth -unregulated cell division can develop into cancer
79
stem cell
undifferentiated cells that are ablet o differentiate into specialized cell types
80
two types of stem cells
- embryonic -adult (characterized by their potency)

Biology- Sac 1 (8 decks)

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