Biology Unit Flashcards
1
Q
What does the Cell Membrane do?
A
- Transports
- Serves as a protective barrier
- Recognition
2
Q
What does the Nucleus do?
A
- Contains DNA
- Directs cell activity
3
Q
What does the Cytoplasm do?
A
- Jelly-like
- Contains nutrients
4
Q
What does the Cell Wall do?
A
PLANTS ONLY
- Rigid
- Provides strength and support
5
Q
What does the Chloroplast do?
A
- PLANTS ONLY*
- Contains chlorophyll for photosynthesis
6
Q
What does the Vacuoles/Vesicles do?
A
- Transports and stores nutrients
- Membrane bound
7
Q
What does the ER (Endoplasmic Reticulum) do?
A
- Transports materials
- Rough ER ——–> with ribosome
- Smooth ER ———> no ribosome
8
Q
What does the Ribosome do?
A
- Site of protein synthesis
- On ER (rough)
9
Q
What do the Lysosomes do?
A
- Digestion
- Membrane bound
10
Q
What does the Golgi Apparatus do?
A
- Receives from ER
- Packages for transport out of cell
11
Q
What does the Mitochondria do?
A
- Cell respiration to make ATP
12
Q
What is ATP (Adenosine Triphosphate)
A
A molecule that carries energy within cells.
13
Q
What does the Centrioles do?
A
- Used in cell reproduction
14
Q
What are cell membranes made up of?
A
Bilayer of phospholipids
15
Q
What is the composition of the phospholipid bilayer?
A
Head - phosphate & glycerol (hydrophilic)
Tail - fatty acid (hydrophobic)
16
Q
Why does the phospholipid bilayer form?
A
Since the head of a phospholipid is hydrophobic it is attracted to the water molecules in the cytoplasm and outside the cell and because the tail is hydrophobic it is repelled from the water inside and outside the cell, forming the bilayer
17
Q
What role do proteins play in a membrane?
A
- Help transport substances across the membrane
- Cell to cell communication
18
Q
How to substances enter the membrane?
A
- Small particles (ex. H2O, C6H12O6) can fit in-between the phospholipids
- Membrane proteins stick out of bilayer and bind to molecules to let them in
19
Q
What is passive transport?
A
- Molecules moving across membrane
- High concentration ——–> low concentration
- No energy needed
20
Q
What are the ways of passive transport?
A
- Diffusion
- Osmosis
- Facilitated diffusion
21
Q
What is a hypotonic solution?
A
- A solution that contains a higher concentration of water/solvent than salt/ solute
- Hypotonic CELLS lose water
22
Q
What is a hypertonic solution?
A
- A solution that contains a higher concentration of salt/solute than water/solvent
- Hypotonic CELLS lose water
23
Q
What is an isotonic solution?
A
- A solution that contains an equal concentration of both water/solvent and salt/solute
- Water moves in and out at the same rate
24
Q
What happens to a living cell with too much/too little water (osmosis in living cells)
A
- Burst (too much water)
- Shrivel (not enough water)
25
What does a carrier protein do?
Changes shape for the particles to allow them into the cell membrane
26
What does a channel protein do?
Creates a tunnel for particles to allow them into the cell membrane
27
What is active transport?
- Cells moving across the membrane
- Low concentration -------> High concentration
- Energy needed (ATP)
28
What is endocytosis?
- Cell membrane forms a pocket for substances to be transported
- Pinches off as a vesicle which transports contents to other locations in the cell or to the vacuole for storage
29
What are the 3 types of endocytosis?
1. Phagocytosis -----> "eating" large particles
2. Pinocytosis -----> "drinking" fluid particles
3. Receptors -----> proteins protruding the membrane detect and bind to specific compounds that are needed
30
What is exocytosis?
- The opposite of endocytosis
| - Materials stored in vesicles or vacuoles (waste) are released and exit the cell
31
How does cell size correlate with diffusion?
Cell size determines the SA/V ratio which also affects diffusion rates
32
Why does the SA/V ratio affect diffusion rates?
The more surface area, the more access cells have to leave the membrane, but when a cell's size increases, the volume increases faster than the SA. This means there is more substance, but less surface area for it to leave, leading to a less efficient diffusion rate.
33
What is a Multicellular Organism?
An organism that consists of more than one cell
34
Define: Organelles
Organelles within a cell perform the specialized functions
35
Define: Cell
Cells are the basic unit of organization in an organism (smallest functional unit of life)
36
Define: Tissue
Tissue is a cluster of cells similar in structure and function
37
Define: Organ
Organ if a group of tissues working together to perform a specialized function
38
Define: System
Systems are made up if multiple organs functioning together at a high level of organization
39
What is the root system? What does it do and where is it found?
The root system of a plant is below the ground and its main functions are to take in oxygen, water and nutrients from the soil, to move them up through the plant and to store a reserve of foods.
40
What is the shoot system? What does it do and where is it found?
The shoot system of a plant is found above the ground where it absorbs the light needed for photosynthesis and consists of stems, leaves, and the reproductive parts of the plant.
41
What is the formula for photosynthesis?
(6)CO2 + light + (6)H2O --------> C6H12O6 + (6)O2
Enters Sunlight Transported Exits stomata
stomata (phloem)
42
What is Cellular Respiration?
The opposite of photosynthesis
43
Where is the majority of photosynthesis performed?
In the leafs of a plant
44
What are the differences between multicellular organisms and unicellular organisms?
Multicellular organisms can have...
- Increased size
- A variety of specialized cells
- The ability to survive in a wider range of environments
45
Cells must be _________ to maximize SA/V ratio
Cells must be SMALL to maximize SA/V ratio
46
Having many cells makes it possible for different groups of cells to become ___________.
Having many cells makes it possible for different groups of cells to become SPECIALIZED
47
Cells vary in ______ and ______ depending on ________
Cells vary in SIZE and SHAPE depending on FUNTION
48
What is the basic organization in a multicellular organism?
Atom --> Molecule --> Organelles --> Cell --> Tissue --> Organ --> Organ System
49
What are stem cells?
Cells that do not have a certain function yet
50
What happens to the new cells when a stem cell is divided?
When they divide, each new cell has the potential to stay a stem cell or become another type of cell with a more specialized function
51
What are epidermal cells?
- Protective skin
- Covers top and bottom of leaves
- Secretes waxy substance (cuticle)
52
What is the stomata (or stoma)
- Mostly found on the bottom of leaf
| - Pores that allow the exchange of gasses
53
What are guard cells?
- Found on either side of the stomata
| - Control gas exchange by changing shape
54
What is the mesophyll made up of?
- Palisade tissue cells
- Spongy tissue cells
- Vascular Tissue cells
55
What are palisade tissue cells?
- Long, narrow cells tightly packed together under the leaf's upper layer
- Main type of photosynthetic cells
- Contain the most chlorophyll
56
What are spongy tissue cells?
- Contain chloroplasts (less than palisade tissue)
- Round, loosely packed cells below palisade cells
- Have air space surrounding to allow for gas exchange
57
What are vascular tissue cells?
- Series of tubes transporting fluids throughout the plant
| - Arranged in vascular bundles (xylem and phloem)
58
What is the gas exchange in plants?
Gas exchange is the process where water and oxygen leave the plant and carbon dioxide enters the plant leaves.
(CO2 enters -----> H2O + O2 are released)
59
_________ are the most important gas-exchange organ in plants
LEAVES are the most important gas-exchange organ in plants
60
What is transpiration? When does this happen?
Transpiration is when plants lose water during gas exchange
61
What role do the stomata and guard cells play in the gas exchange?
They allow gasses in and out that are diffused through membranes of spongy tissue cells
62
The stomata opens and closes depending on the _________. This is controlled by the _________________ in the _________.
The stomata opens and closes depending on the GUARD CELLS. This is controlled by the AMOUNT OF WATER in the GUARD CELLS.
63
When the stomata is open gasses ______________ and when closed gas and water exchange is ___________.
When the stomata is open gasses CAN BE EXCHANGED and when closed gas and water exchange is REDUCED.
64
What is turgor pressure? What will happen without the proper amount of this?
The water pressure in plant cells that allows them to stay rigid. Without the proper amount, plants will wilt
65
When is there an increase in turgor pressure? What does this cause?
During osmosis. This causes the stomata to open.
66
When is there a decrease in turgor pressure?
During transpiration. This causes the stomata to close.
67
During the day the stomata are usually ________.
During the day the stomata are usually OPEN.
68
At night the stomata are usually ________.
At night the stomata are usually CLOSED.
69
What are lenticels? How does the gas exchange occur in them?
Woody plants (ex. trees). They contain openings in their bark for the gas exchange to occur.
70
What is the vascular system made up of?
Xylem - water and mineral transport
Phloem - sugar transport
Bundle Sheath - holds the xylem and phloem together
71
Where is the vascular bundle present in plants?
The leaves, roots, and stems of plants.
72
What is the phloem composed of?
Living cells which contain cells walls with pores
73
The xylem is composed of _________ whereas the phloem is composed of _________.
The xylem is composed of DEAD CELLS whereas the phloem is composed of LIVE CELLS.
74
Without the xylem to perform ______________, the plant cannot perform _______________.
Without the xylem to perform WATER TRANSPORT, the plant cannot perform PHOTOSYNTHESIS.
75
What is the purpose of the xylem?
Transports waters and minerals from the soil to the leaf
76
How is water transported into the xylem?
Water enters the plant through the epidermal layer of root hairs and diffuses by osmosis into the xylem vessels.
77
How are minerals transported into the xylem?
Through facilitated diffusion or active transport
78
What is xylem sap? Where and how is it transported?
A mixture of H2O and minerals. The xylem sap enters the xylem where it is then carried up the stem and into the leaves through veins on the leaf. The leaf cells then absorb the sap.
79
What helps sap travel up the stem against gravity?
- Cohesion
- Adhesion
- Root pressure
- Transpiration
80
What does cohesion refer to when helping sap travel up the stem?
Water-Water Attraction:
| The attractive forces between water molecules
81
What does adhesion refer to when helping sap travel up the stem?
Water-Surface Attraction:
| The attractive forces between water molecules and molecules of a surface
82
What does transpiration (or transpirational pull) refer to when helping sap travel up the stem?
As water evaporates from the surface of leaf cells, cohesion forces will force water up the xylem vessels in the leaf to replace the water. As a result, more water is pulled up from other xylem vessels in the plant as well.
83
What does root pressure refer to when helping sap travel up the stem?
Turgor pressure inside the root xylems forcing water up the xylem
84
What is the purpose of the phloem?
Transports glucose (dissolved in solution) throughout the plant
85
What is the phloem composed of?
Tubes of living cells, containing cell walls with pores.
86
Why do the cell walls of the phloem require pores?
In order to exchange materials with nearby cells
87
What is phloem sap and when is it produced?
Sugars that are produced during photosynthesis
88
Where and how is the phloem sap transported?
It is transported throughout the plant via the phloem vessels.
89
What is phloem sap used for?
Growth, reproduction or it is stored in the roots.
90
When the concentration of sugar in phloem cells _______, water begins to _______________ via osmosis. This ________ turgor pressure as well.
When the concentration of sugar in phloem cells INCREASES, water begins to MOVE INTO THEM via osmosis. This INCREASES turgor pressure as well.
91
An increase in turgor pressure __________________ of the phloem cells into __________ cells.
An increase in turgor pressure FORCES SURGAR OUT of the phloem cells into NEIGHBOURING cells.
92
What happens as phloem sap travels to the roots (down the concentration gradient)
Some of it leaves the phloem through its cell wall's pores and nourishes surrounding tissue
93
_______ vessels have a one-way flow ONLY whereas _______ vessels have a two-way flow
XYLEM vessels have a one-way flow ONLY whereas PHLOEM vessels have a two-way flow
94
What are tropisms?
A plant's response to its environment
95
What is phototropism?
Growth of a plant toward the light source to maximize photosynthesis. Plants will ALWAYS exhibit this.
96
How does phototropism occur?
Auxins (a plant growth chemical) move to the area of the stem facing away from light and cause the cells located there to elongate. This allows the stem to "bend" towards the light
97
What is gravitropism?
The growth of a plant in response to gravity.
98
What type of gravitropism do roots exhibit?
Positive because they grow down (in the direction of gravity)
99
What type of gravitropism do stems exhibit?
Negative because they grow up (against gravity)
100
What is a nastic response?
The response a plant makes to touch
101
What is a sleep movement response?
The response a plant makes to the time of day (daytime or night time)
