Unit 2 - Cells: Structures, Functions, and Processes Flashcards
1
Q
What are the three kinds of nucleic acids?
A
DNA, RNA, and ATP
2
Q
What is ATP?
A
ATP is the energy currency
3
Q
Why are eukaryotic cells divided into compartments?
A
They have specialization, so different environments might be needed for different tasks.
4
Q
What is the cell membrane?
A
A lipid bilayer, or a double layer of phospholipids.
5
Q
What do we call a membrane that allows some materials to pass but not others?
A
Selectively permeable
6
Q
What kind of life belongs to the prokaryotes?
A
Bacteria and archaea
7
Q
What superlative describe bacteria and archaea?
A
They are the smallest and most metabolically diverse forms of life.
8
Q
What does “metabolically diverse” mean?
A
It means they can eat and use many different things as a food source or building material
9
Q
How are bacteria and archaea similar?
A
In appearance and size
10
Q
How are bacteria and archaea different?
A
In structure and metabolism
11
Q
What are the basic body parts of bacteria and archaea?
A
Cytoplasm (with ribosomes) DNA in a nucleoid Cell wall Plasma membrane Capsule Pilus (pl. pili) Flagellum
12
Q
What can get through a cell’s membrane?
A
Gases, water, and small molecules.
13
Q
Why can’t molecules that are hydrophilic cross the lipid bilayer?
A
Because it’s oily, and hydrophiles love them waters.
14
Q
What is an ion?
A
An atom that has lost of gained one or more electrons.
15
Q
Why can’t ions cross the cell membrane?
A
Because they’re polar.
16
Q
What is facilitated diffusion?
A
It makes the diffusion of molecules across the cell membrane possible with the help of membrane proteins.
17
Q
Is facilitated diffusion active or passive?
A
Note the word “diffusion”; still from high to low, still passive, but it just needs a transport protein.
18
Q
What is active transport?
A
The movement of molecules from a less crowded to a more crowded area (against the concentration gradient)
19
Q
What do you call the outside of a cell?
A
Extracellular fluid (ECF)
20
Q
What is step one in active transport?
A
The active transport of ions into cells (although it can be other things)
21
Q
What does hypotonic mean?
A
A high concentration of water and a low concentration of solute.
22
Q
What does hypertonic mean?
A
A low concentration of water and a high concentration of solute.
23
Q
How do ions get into a cell?
A
The cell pumps them in through active transport
24
Q
What is step two of active transport?
A
The net movement of water into the cell by osmosis.
25
What does active transport require to work?
Energy (ATP) and membrane proteins
26
Why do we have electrolyte drinks?
Because they help move ions into cells, which means that the water follows, thereby helping our body absorb the water.
27
What needs to be the same about the solutes for osmosis to stop?
The RATIO of water to other ingredients in the solute.
28
What is the driving force behind osmosis?
To even out the concentration of water in a solute.
29
What is endocytosis?
The process by which cells take in particles that are too big for transport proteins.
30
What is exocytosis?
The process by which cells expel particles that are too big for transport proteins.
31
In a cell, what produces ATP?
Mitochondria
32
In a cell, what produces polypeptides?
Ribosomes
33
In a cell, what produces ribosome parts?
The nucleolus
34
In a cell, what protects and holds the DNA?
The nucleus
35
In a cell, what controls protein synthesis?
The nucleus
36
In a cell, what modifies and assembles proteins?
The rough ER
37
In a cell, what produces lipids?
The smooth ER
38
In a cell, what are the transport proteins called?
Vesicles
39
In a cell, what sorts and labels various proteins?
The Golgi apparatus
40
In a cell, what takes care of intracellular digestion?
Lysosome
41
In a cell, what controls which substances go in and out?
Cell membrane
42
In a cell, what holds the internal structures?
Cytoplasm
43
Why are cells small?
So that they have a larger surface area to allow for more substances to pass through the membrane
44
What is a good analogy for why cells need to be small?
Think of a big building and fire exits.
45
Smaller cells have a higher what?
surface-area-to-volume ratio
46
What four things does a cell want to let in?
Oxygen
Water
Food molecules
Protein
47
Why does a cell need oxygen?
To burn, even in the body, you need oxygen! So we need oxygen for ATP production
48
What is passive transport?
- Passive transport: The movement of molecules from a more crowded to a less crowded area without the use of energy, i.e. by diffusion
49
What is diffusion?
Random movement of molecules, from high to low concentrations
50
What is osmosis?
The movement of water through a semi-permeable membrane.
51
What are the differences and similarities between the things that a cell wants to let in?
o Oxygen and water are smaller and can move freely across the phospholipid barrier
o But food molecules and proteins are too big, so they need membrane protein gates
52
What is membrane trafficking?
The process by which cells take in (endocytosis) and expel (exocytosis) particles that are too big for transport proteins, as well as substances in bulk
53
What does membrane trafficking require?
The formation and movement of vesicles
54
In membrane trafficking, do the particles cross the lipid bilayer?
No. When a vesicle fuses with the cell wall, the lipid bilayers actually fuse, so that nothing ever technically “crosses” the plasma membrane.
55
What is a producer?
Organism that harvests its energy directly from the environment, usually in the form of light energy through photosynthesis.
56
How does a producer get food?
It makes its own, mostly through photosynthesis
57
What organisms are producers?
Plants (and others as well)
58
What's a consumer?
An organism that harvests its energy by consuming other organisms, either parts, whole, remains or wastes.
59
How do both producers and consumers release energy?
Through cellular respiration?
60
What kinds of organisms are consumers?
Animals, most fungi, many protists, and bacteria
61
What happens to nutrients in the cells of producers and consumers?
They become incorporated into the cells and are eventually released by decomposition, some cycling back to producers
62
What happens to matter in an ecosystem?
It cycles around
63
What happens to energy in an ecosystem?
It flows through and out
64
What happens to all energy that enters the world of life?
It eventually flows out of it, mainly as heat released back to the environment
65
What is cellular respiration?
The processes whereby certain organisms obtain energy from organic molecules
66
Carbon + water =
carbohydrates!
67
What is the cellular respiration formula?
C6H12O6 + 6O2 => Released energy + 6CO2 + 6H2O
68
What is C6H12O6?
Carbohydrates
69
What is the formula for carbohydrates?
C6H12O6
70
How many carbohydrates are there in glucose?
6
71
There are 6 carbohydrates in glucose, so what is that formula?
(C + H2O) x 6 = C6H12O6
72
What are the six main points of the cellular respiration formula in words?
1. Burns sugars for energy
2. Oxygen is used
3. Energy is released
4. Occurs in the mitochondria of most cells
5. Carbon dioxide is produced
6. Water is produced
73
What types of cells have lots of mitochondria and why?
Muscle cells! Those cells contract a lot, so they need a lot of ATP produced, and that’s why they need lotsa mitochondria
74
What are chloroplasts?
Organelles in plants not animals
75
What do chloroplasts contain?
The green pigment chlorophyll
76
What are the stacks in chloroplasts called?
Thylakoids
77
What do chloroplasts do?
Photosynthesis! (makes sugars)
78
What is the point of photosynthesis?
Making sugar from sunlight
79
What is the energy conversion that happens with photosynthesis?
Light energy is turned into chemical energy
80
What is the formula for photosynthesis?
6CO2 + 6H2O + light energy => C6H12O6 + 6O2
81
Where does photosynthesis occur?
Only in cells with chloroplasts
82
Where does photosynthesis NOT occur?
Roots, bark, etc. Anything NOT green.
83
What kind of energy does photosynthesis produce?
Chemical energy
84
How does a consumer get food?
It eats
85
What happens in the growth stage of interphase?
The cell grows and produces more organelles
86
What happens in the DNA synthesis stage of the interphase?
The DNA molecules are replicated
87
What happens in the preparation for division stage of interphase?
Materials needed for mitosis are produced
88
What is the function of cell division in bacteria?
Reproduction, i.e. making more bacteria
89
What is the function of meiosis in the female body and where does it happen?
It produces egg cells in the ovaries
90
What is the function of meiosis in the male body and where does it happen?
It produces sperm cells in the testes.
91
How does "crossing-over" lead to genetic variations in gametes?
The exchange of DNA segments creates new combinations of paternal and maternal DNA on each chromosome.
92
The strawberry plant: What is the advantage of asexual reproduction?
It is quick, requires little energy, and only one parent plant is needed.
93
The strawberry plant: What is the disadvantage of asexual reproduction?
The new plant is a clone of its parent and therefore equally vulnerable to a disease.
94
The strawberry plant: What is the advantage of sexual reproduction?
New genetic varieties are produced, which may provide protection against disease, and the seeds may end up in a new environment where more plants can grow.
95
The strawberry plant: What are the four disadvantages of sexual reproduction?
It requires to parents, a pollinator, a lot of energy, and a lot of time.
96
The strawberry plant: Why will it reproduce asexually?
To take advantage of a favourable environment.
97
Why do cells divide in unicellular organisms?
To reproduce
98
Why do cells divide in multicellular organisms?
To grow or to maintain/repair tissues
99
What is a chromosome?
An organized (wound up) structure of DNA that is found in the nucleus of cells when the cell is dividing
100
A chromosome is what kind of molecule?
DNA
101
When do we call DNA a chromosome?
When it is folding up in a very specific way
102
What happens to DNA when a cell is NOT dividing?
The DNA is all spaghetti-like; still organized, but everywhere
103
What is a centromere?
The part in the middle of a chromosome that connects the two copies
104
What do you call the part in the middle of a chromosome that connects the two copies?
The centromere
105
How many sets of chromosomes does each body cell have?
2, one paternal and one maternal
106
What are homologous chromosomes?
The ones that carry the same information but are NOT identical.
107
How many sets of homologous chromosomes do we have?
23
108
What do we call the chromosome sets that carry the same type of genes for the same characteristics?
Homologous chromosomes
109
What do we call two different types of the same gene?
Alleles
110
What are alleles?
Different types of the same gene
111
Are homologous chromosomes always the same size and shape?
Yes, except for our reproductive genes.
112
Human cells have two of each kind of chromosome, which is called...?
Diploid
113
What do we call cells which only have one type of each chromosome?
Haploid
114
What is a diploid cell?
A cell with two of each kind of chromosome
115
In humans, which type of cell is haploid?
Sex cells
116
What is a haploid cell?
A cell with only one kind of chromosome
117
What is meiosis?
The division process that halves the chromosome number; sexual reproduction
118
What does crossing over do?
It mixes up paternal and maternal alleles on homologous chromosomes.
119
What are the three parts of interphase?
G1: Growth
S: DNA synthesis
G2: Getting ready for division
120
What are the three stages of the cell cycle?
Interphase
Mitosis
Cytoplasmic division
121
What are the four stages of mitosis?
Prophase
Metaphase
Anaphase
Telophase
122
What is chromatin?
The DNA molecules when they're not all folded up, aka the spaghetti
123
What happens in the prophase of mitosis?
- The chromatin draws together to create chromosomes
| - Spindle fibers form and the nuclear membrane breaks down
124
What do spindle fibers do?
They helps move chromosomes around
125
What are spindle fibers made of?
Proteins that are part of the cytoskeleton
126
What can you see/not see during the prophase of mitosis?
We can't see the nucleus anymore but we can see the chromosomes as they begin to fold up
127
What happens in the metaphase of mitosis?
The chromosomes line up at the cells equator and the spindles attach to the sister chromatids
128
Where do spindles attach to the chromosomes?
At the centrioles
129
What happens in the anaphase of mitosis?
Sister chromatids are pulled apart at the centromere
130
What happens in the telophase of mitosis?
- Chromosomes reach the poles
- The nuclear membrane begins to reform
- Cleavage furrow forms, pinchbe the cells in two
- Chromosomes begin to unwind
131
What happens during cytoplasmic division?
The cell breaks in two and the cytoplasm is divided
132
How does cytoplasmic division happen in animal cells?
With a cleavage furrow; like when a balloon is pinched
133
How does cytoplasmic division happen in plant cells?
A cell plate is formed
134
Where does meiosis happen?
Only in reproductive organs
135
What is the point of meiosis?
To create variety
136
In humans, where does mitosis occur?
Everywhere
137
In humans, where does meiosis occur?
Only in the ovaries or testes
138
What is a gamete?
A mature, haploid reproductive cell, e.g. an egg or a sperm
139
What is a zygote?
A diploid cell formed by fusion of two gametes; the first cell of a new individual
140
What is the difference in the stages of mitosis and meiosis?
There is meiosis I and II; the second stage is exactly the same as mitosis
141
How many divisions are there in meiosis?
2
142
What happens in the prophase of meiosis I?
- Spindles form
- The nuclear membrane breaks up
- The 4 chromatids of of the homologous chromosomes connect
- Crossing over occurs
143
What happens in the metaphase of meiosis I?
Tetrads line up at the cell's equator, side-by-side in pairs (NOT in a single line like mitosis)
144
What are chromatids?
The single strands of DNA that make up a chromosome
145
What are sister chromatids?
Exactly the same chromatids connected at the centriole of a chromosome
146
How are the paternal and maternal chromosomes oriented in the metaphase of mitosis I?
Randomly.
147
What happens in the anaphase of meiosis I?
Homologous chromosomes separate and begin heading toward the poles
148
What happens in the telophase of meiosis I?
A complete set of chromosomes reach each pole and a nuclear envelope forms, so two haploid nuclei form.
