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SBI 4U1 Gr 12 Biology > Unit 1 (Biochemistry) - Chapter 2 > Flashcards

Unit 1 (Biochemistry) - Chapter 2 Flashcards

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1
Q

What are cell organelles?

(2.1)

A

an internal functional structure that is located within the cytosol of the cell

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2
Q

What is the plasma membrane?

(2.1)

A

a dynamic barrier that surrounds the cytosol of the cell

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3
Q

What is the endomembrane system?

(2.1)

A

a group of interacting organelles between the nucleus and the plasma membrane

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4
Q

What is the endoplasmic reticulum (ER)? What does is the difference between the Rough ER and the Smooth ER?

(2.1)

A
  • It is a membrane bound organelle that is folded into flattened sacs and tubes, a network of interconnecting membranes distrbuted throughout the cytoplasm
  • It consists of the lumen, a separate part of the cell with a distinct protein and ion composition
  • The Smooth ER has no ribosomes, so it does not make proteins.
  • The Rough ER has ribosomes attatched to the surface. The proteins fold and take on their complex structure
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5
Q

What are vesicles?

(2.1)

A
  • membrane-enclosed, saclike organelles
  • A small, membrane-bound organelle that may transport, store or digest substances within a cell
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6
Q

What are vacuoles? What is their role in the cell?

(2.1)

A
  • a vesicle/liquid filled organelle that stores and disposes waste
  • It also aids in cellular metabolism and water balance
  • Amino acids, sugars and ions accumalate here
  • Helps develop turgor pressure
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7
Q

What are lysosomes?

(2.1)

A
  • Lysosomes are vesicles containing digesive enzymes that come in part from the Golgi
  • Lysosomes are sites for breakdown of food and foreign material brought into the cell by phagocytosis.
  • Lysosomes are sites where digestion of spent cellular components occurs, a process called autophagy
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8
Q

What is the Golgi Apparatus?

(2.1)

A
  • The Golgi apparatus is an organelle that processes and packages proteins
  • It consists of flattened membranous sacs and small membrane-enclosed vesicles
  • It has three roles:
    1) Receive proteins from the ER and further modify them
    2) Concentrate, package, and sort proteins before they are sent to their destinations
    3) Synthesizes polysaccharides for plant cell walls
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9
Q

What is the primary function of the mitochondria (no, not being “the powerhouse of a cell” lol)? Do all eukaryotes and prokaryotes have this organelle?

(2.1)

A
  • Mitochondria convert chemical energy of fuel molecules into ATP
  • Nearly all eukaryotic cells have mitochondria but prokaryotes do not
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10
Q

Describe prokaryotes. What do they have and what do they not have?

(2.1)

A
  • All prokaryotes have a plasma membrane
  • All have a region called the nucleoid which is where the DNA is concentrated
  • They have no nucleus or other membrane-enclosed compartments, they lack distinct organelles
  • The cytoplasm consists of the nucleoid, ribosomes, and a liquid portion called the cytosol (the more precise term)
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11
Q

Describe eukaryotic cells. What do they have?

(2.1)

A
  • Eukaryotic cells have a membrane-enclosed nucleus
  • They tend to be larger than prokaryotic cells
  • Have a variety of organelles
  • Have a protein scaffolding called the cytoskeleton
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12
Q

What is the nucleus? What is it enclosed by?

(2.1)

A
  • The nucleus is the site of most cellular DNA, which, with associated proteins, comprises chromatin
  • it is enclosed by a two-layer membrane called the nuclear envelope (formed by two lipid bilayers)
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13
Q

What are the two lipid bilayers of the nuclear membrane pierced by?

A
  • The two lipid bilayers are pierced with nuclear pores.
  • They connect the interior of the nucleus with the rest of the cytoplasm.
  • A pore complex, consisting of eight large protein
    granules, surrounds each pore.
  • RNA and proteins must pass through these pores
    to enter or leave the nucleus.
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14
Q

What are ribosomes? What do they do and where are they found? What do they consist of?

(2.1)

A
  • Ribosomes are the sites of protein synthesis.
  • In eukaryotes, functional ribosomes are
    found free in the cytoplasm, in mitochondria, bound to the endoplasmic reticulum, and in chloroplasts.
  • They consist of a type of RNA called ribosomal RNA, and more than 50 other proteins.
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15
Q

What are plastids? What are the three common types of plastids?

(2.1)

A
  • A membrane-bound organelle that is involved in photosynthesis and storage in plants and algal cells.
  • The three types are chloroplast, chromoplast and amyloplasts
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16
Q

What are chloroplasts?
What do they do?

(2.1)

A
  • They harvest the energy of sunlight to produce sugar
  • Chloroplasts are surrounded by two layers
  • The internal membranes are arranged as thylakoids and grana. These membranes contain chlorophyll and other pigments.
  • The fluid in which the grana are suspended is called the stroma.
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17
Q

What is endosymbiosis?

(2.1)

A
  • Endosymbiosis may explain the origin of
    mitochondria and chloroplasts.
  • According to the endosymbiosis theory, both
    organelles were formerly prokaryotic organisms
    that somehow became incorporated into a larger
    cell.
  • Today, both mitochondria and chloroplasts have
    DNA and ribosomes, and are self-duplicating
    organelles.
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18
Q

What are chromoplasts? What are amyloplasts?

(2.1)

A
  • an organelle that makes and stores pigment other than chlorophyll
  • Amyloplast is an organelle that stores starch
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19
Q

a) What is the cytoskeleton and why is it important?
b) What are the three types of cytoskeletal components

(2.1)

A

a) - A dynamic system of filaments that maintains cell shape and support
- Provides the mechanisks for cell movement
- Helps with cell division
- Enables the cell and inner organelles to move around

b) the three types of cytoskeletal components are microfilaments, intermediate filaments, and microtubules

20
Q

What are microfilaments?

(2.1)

A

a fibre structure made from actin that is part of the cytoskeleton and is located in the cytosol of cells

21
Q

What are microtubules?

(2.1)

A
  • Microtubules are hollow cylinders made from tubulin protein subunits
  • They provide a rigid intracellular skeleton for some cells, and they function as tracks that motor proteins can move along in the cell
  • They can change form
22
Q

What are cilia? What are flagella?

(2.1)

A
  • Flagella is a whiplike tail that is used in porpulsion of both prokaryotic and eukaryotic cells through fluid
  • Cilia are tiny hairlike structures that move water and mucus in eukaryotes; used for movement of prokaryotic cells.
23
Q

Describe the plant cell wall (NOTE: Animal cells do not have a cell wall but protists and fungi do).

(2.1)

A
  • The plant cell is composed of cellulose fibres embedded in a matrix of other complex polysaccharides and proteins
  • The cell wall provides a rigid strucutre for the plasma membrane under turgor pressure giving important support
  • Protects the plant from infectious diseases
24
Q

What are cell junctions?

(2.1)

A
  • A structure that allows cells that are surrounded by a wall or secretions to interact with other cells and the surrounding environment so they are not isolated
  • Helps cells with cell to cell recognition and tissue formation
25
Q

Distinguish between primary cell walls and secondary cell walls

(2.1)

A
  • Primary cell walls is the first cellulose coating that surrounds a plant cell, it is thin and alllows the growing cell to enlarge
  • Secondary cells are a sercondary coating that is added to the plant cell wall, is more rigid and thicker
  • It is formed after the cell is done enlarging
26
Q

What is the Extracellular matrix (ECM)?

(2.1)

A
  • The ECM is non-living mixture of fibrous proteins and polysaccharides that supports and protects cells
27
Q

What is the fluid mosaic model?

(2.2)

A

the idea that a biological membrane consists of a fluid phospholipid bilayer, in which proteins are embedded and float freely

28
Q

Why is the fluid mosaic model used to describe the strucutre of the plasma membrane? (consider both thr words “fluid” and “mosaic”)

(2.2)

A

Fluid:
- Lipids are like the water of a lake in
which proteins “float.”
- Proteins can move laterally.

Mosaic:
- Membrane proteins are embedded
in the lipid bilayer.
- Carbohydrates attach to lipid or
protein molecules on the membrane,
generally on the outer surface.

29
Q

What are the two kinds of proteins are within membranes? (refer to the diagram on pg. 82)?

(2.2)

A

a) 2 kinds of proteins include:
- Integral proteins (big blue figures including the blue transport protein in the middle)
- Peripheral proteins (smaller light green figures that look like eggs)

30
Q

a) What is a glycolipid?
b) What is a glycoprotein?

(2.2)

A
31
Q

Are membranes symmetrical? Why or why not?

(2.2)

A

Lipid asymmetry provides the two sides of the plasma membrane with different biophysical properties and influences numerous cellular functions.

32
Q

What influences fluidity of the lipid bilayer?

(2.2)

A

Three key factors influence cell membrane fluidity:
- temperature
- cholesterol
- The kind of fatty acids in the phospholipids that form the cell membrane.

33
Q

What is the role of cholesterol in membranes?

(2.2)

A
  • at high temps - it stabilizes, reducing fluidity
  • at low temps - it keeps the membrane fluid
34
Q

What 4 roles do membrane proteins play?

(2.2)

A
  • Transport
  • Enzymatic activity
  • Tiggering signals
  • Attatchment and recognition
35
Q

Distnguish between integral and peripheral proteins in terms of structutre and function

(2.2)

A

Integral:
- a protein that is embedded in the lipid bilayer
- All integral proteins have at least one region that interacts with the hydrophobic core of the membrane

Peripheral:
- a protein on the surface of the membrane
- held by H-bonds or ionic bonds to membrane surfaces
- mostly on tjhe cytosol side
- Some hold integral proteins in place

36
Q

a) What is Passive transport?
b) What are the two types of passive transport? Describe both types

(2.4)

A

a) The movement of a substance across a membrane without using up (or requiring) energy

b)
- Simple Diffusion - the ability of small and non-polar substances to move across a membrane unassisted

  • Facilitated Diffusion - The facilitated (assisted) transport of ions and polar molecules through a membrane via protein complexes
37
Q

Give a full definition of diffusion and why it occurs

(2.4)

A
  • Diffusion is the net movement of a substance from a region of higher concentration to a region of lower concentation
  • It occurs because molecules are in constant motion and, in an ideal closed environment, tend to become uniformly distributed in space.
38
Q

What is dynamic equilibrium?

(2.4)

A
  • the state in which continuous action results in balanced conditions, no net change of concentration
39
Q

a) What are transport proteins?
b) What are the two types of transport proteins? Describe each.

(2.4)

A

a) An integral membrane protein that privdes a pathway for molecules to cross a membrane
b) The two types of proteins:
- Channel proteins - a hydrophilic pathway in a membrane that enables water anf ions to pass through
- Carrier proteins - a protein that binds to a molecule

40
Q

What is Active Transport

(2.4)

A

The movement of substances across membranes against their concentration gradient using pumps

41
Q

What is osmosis?

(2.4)

A

the passive movement of diffusion across a membrane

42
Q

What are the 3 term properties of solutions? Describe each.

(2.4)

A

1) Hypotonic:
- the property of a solution that has a lowet solute concentration than another solution

2) hypertonic:
- the property of a solution that has a higher solute concentration than another solution

3) isotonic:
- the property of a solution that has the same solute concentration as another solution

43
Q

Distinguish between Endocytosis and Exocytosis.

(2.4)

A
  • Endocytosis moves aggregate molecules into the cell
  • Endocytosis moves proteins and wastes out of the cell
44
Q

Digestion occurs in a vacuole after it fuses with a

A

Lysosome

45
Q

Besides the nucleus, which organelles contain DNA?

A

Chloroplasts and mitochondria

46
Q

What will happen to a plant cell in a hypertonic solution?

A

There will be a net movement of water out of the cell and it will shrink.

47
Q

Which organelle is associated with the production of ribosomes?

A

nucleolus

SBI 4U1 Gr 12 Biology (5 decks)

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