Exam 2 Flashcards
(134 cards)
1
Q
What did seed plants evolve from?
A
Spore-bearing progymnosperms.
2
Q
When did seed plants first appear?
A
Around 300 million years ago (MYA).
3
Q
Which group of seed plants appeared first?
A
Gymnosperms.
4
Q
How much later did angiosperms appear after gymnosperms?
A
About 100 MYA later.
5
Q
What drives the evolution of seed plants?
A
Whole genome duplications.
6
Q
What are the potential outcomes of whole genome duplication?
A
- Gene loss (degeneration)
- Neofunctionalization
- Subfunctionalization
7
Q
What is an example of a protein that evolved from gene duplication?
A
Antarctic ice fish antifreeze protein.
8
Q
What percentage of modern plants are seed plants?
A
96%.
9
Q
What are the advantages of seeds?
A
- Embryo protection via a hardened seed coat
- Dormancy
- Stored food source
- More effective dispersal
10
Q
What is the protective outer layer of a seed called?
A
Integument.
11
Q
What is contained within the ovule of female gametophytes?
A
Egg.
12
Q
How do male gametophytes develop?
A
Pollen grains contain cells that develop into sperm.
13
Q
Do seed plants require water for fertilization?
A
No.
14
Q
What is the difference in ovule location between gymnosperms and angiosperms?
A
Gymnosperms have ‘naked seeds’, while angiosperms have ovules enclosed in an ovary.
15
Q
How many extant phyla of gymnosperms are there?
A
Four.
16
Q
Name the four extant phyla of gymnosperms.
A
- Coniferophyta
- Cycadophyta
- Gnetophyta
- Ginkgophyta
17
Q
What are some ecological and economic importance of conifers?
A
- Timber
- Paper
- Resin
- Biofuels
- Taxol (anti-cancer drug)
18
Q
What adaptation helps pines survive dry and cold climates?
A
Needle-like leaves.
19
Q
What is the purpose of resin canals in pines?
A
- Deter insects
- Seal wounds
20
Q
What are the male reproductive structures in pines called?
A
Male cones (pollen cones).
21
Q
What do female cones contain?
A
Ovules.
22
Q
What happens during pollination in pines?
A
Pollen grains land on sticky fluid at micropyle.
23
Q
What is the difference between pollination and fertilization?
A
- Pollination: Transfer of pollen to female structure
- Fertilization: Union of sperm and egg to form zygote
24
Q
How long does it take for the zygote to develop into an embryo in pines?
A
About a year.
25
What is serotiny in pines?
Some pines require fire to trigger seed release.
26
What is polyembryony in pines?
Multiple embryos can form from different eggs in the same ovule.
27
What unique feature does Ginkgo biloba have?
Fleshy seed coatings that smell like vomit.
28
Which gymnosperms have vessel elements in their xylem?
Gnetophytes.
29
What is the main difference between pines and angiosperms?
Pines do not produce flowers or fruits.
30
31
What are the main groups included in Tracheophytes?
Lycophytes, Pteridophytes, Gymnosperms, Angiosperms
## Footnote
Lycophytes (Phylum Lycophyta), Pteridophytes (Phylum Pterophyta), Gymnosperms (4 different phyla), Angiosperms (Phylum Anthophyta)
32
What is the dominant generation in tracheophytes?
Sporophyte generation
## Footnote
Unlike bryophytes, where gametophytes dominate
33
What are the key characteristics of tracheophytes?
* Dominant sporophyte generation
* Reduced gametangia
* Presence of vascular tissue (xylem & phloem)
34
What is the function of xylem in tracheophytes?
Conducts water & minerals
## Footnote
Absorbed through roots
35
What are the components of xylem?
* Sturdy cells with reinforced cell walls
* Secondary xylem = wood (mostly dead cells)
36
What is the main function of phloem?
Conducts nutrients (primarily sucrose)
## Footnote
Sucrose = Glucose + Fructose
37
What is the role of the cuticle in plants?
Prevents water loss
38
What do stomata allow in plants?
Gas exchange (CO₂ in, O₂ out)
## Footnote
Regulates water loss
39
What were the first tracheophytes in the fossil record characterized by?
Only stems (no roots or leaves)
40
What did early tracheophytes likely rely on for nutrient and water absorption?
Symbiotic fungi
41
What are the two key functions of roots in tracheophytes?
* Anchorage to soil
* Water & mineral uptake
42
What advantages do leaves provide to plants?
* Increase photosynthesis capacity
* More stomata → More CO₂ intake → Higher efficiency
43
How many times did roots evolve in tracheophytes?
Twice
44
What are the two types of leaves that evolved in tracheophytes?
* Lycophylls (single-veined leaves)
* Euphylls (multiveined, more efficient for photosynthesis)
45
What are the functions of seeds in seed plants?
* Protects the embryo
* Allows dormancy until conditions are favorable
* Resistant to environmental stress
* Can survive digestion
* Contains food reserves for early growth
46
What are the two major groups of seed plants?
Gymnosperms and Angiosperms
47
What is a key characteristic of angiosperms?
Flowers
48
What do flowers promote in angiosperms?
Outcrossing
49
What are the two types of reproductive structures in flowering plants?
* Carpel (female)
* Stamen (male)
50
What is the term for the female reproductive structure that encloses ovules?
Carpel
51
What occurs during double fertilization in angiosperms?
* One sperm fertilizes egg → Forms zygote
* Second sperm fuses with polar nuclei → Forms triploid endosperm
52
What is the main difference in ovule protection between gymnosperms and angiosperms?
Gymnosperms have naked seeds, while angiosperms have seeds enclosed within ovary
53
What is the structure of a simple pistil?
One unfused carpel
54
What adaptations do wind-pollinated plants exhibit?
* Small, dull petals
* Large anthers & exposed stamens
55
What is the role of pollinators in angiosperm reproduction?
Transfer pollen across populations
56
What are the components of a mature embryo sac?
* 1 egg cell
* 2 synergids
* 3 antipodal cells
* 1 large central cell with 2 nuclei
57
What type of plants are ferns and horsetails classified as?
Pteridophytes
58
What is the significance of sori in ferns?
Clusters of sporangia that produce haploid spores
59
What is the main difference between homosporous and heterosporous plants?
Homosporous plants produce identical spores, while heterosporous plants produce male and female spores
60
What is the term for the coiled young leaves of ferns?
Fiddleheads
61
What are the three main components of a seed?
* Embryo
* Endosperm
* Seed coat
## Footnote
The embryo is the developing plant, the endosperm serves as a nutrient source, and the seed coat is the protective outer layer.
62
What is the function of the seed coat?
Protects seed from environmental damage, chemicals, and digestion
## Footnote
Formed from two integuments.
63
What type of tissue is the endosperm?
Triploid (3n) tissue that stores nutrients for embryo
## Footnote
It provides essential nutrients until the seedling can photosynthesize.
64
What are cotyledons?
Seed leaves that store nutrients in some species
## Footnote
They are part of the embryo.
65
What does the shoot apical meristem develop into?
The plant's stem and leaves
## Footnote
It is a component of the embryo.
66
What does the root apical meristem develop into?
The root system
## Footnote
It is also part of the embryo.
67
What is procambium a precursor to?
Xylem & phloem for vascular transport
## Footnote
It is part of the embryo structure.
68
What is seed dormancy?
Low metabolic activity, reduced water content (5-20%)
## Footnote
It allows seeds to remain viable until conditions are ideal for germination.
69
What triggers germination?
Availability of moisture & oxygen
## Footnote
Oxygen is required for cellular respiration to generate ATP.
70
What are the advantages of seeds?
* Dormancy
* Seed coat protection
* Nutrient storage
* Dispersal
## Footnote
Each advantage contributes to the survival and spread of plant species.
71
What is the oldest viable seed known?
32,000-year-old Narrow-leaf Campion
## Footnote
It was found in permafrost in Siberia.
72
What is serotiny?
Special adaptations that control when a seed germinates
## Footnote
It includes mechanisms like fire-triggered germination.
73
What is an example of fire-triggered germination?
Jack pine cones require high heat to release seeds
## Footnote
Fire reduces competition and increases soil nutrients from ash.
74
What role does moisture play in seed germination?
Leaches inhibitory chemicals from seed coats
## Footnote
This ensures germination only happens when enough water is available.
75
How does animal digestion help in seed germination?
Weakens the seed coat, increasing germination chances
## Footnote
Many fruit trees, including cherries and apples, rely on this mechanism.
76
What type of fruit only develops from angiosperms?
Fruits
## Footnote
They do not occur in gymnosperms like pines.
77
What develops from the ovary in plants?
Fruit
## Footnote
The ovule develops into the seed.
78
What are the three layers of the pericarp?
* Exocarp
* Mesocarp
* Endocarp
## Footnote
These layers form the structure of the fruit.
79
What is an example of a berry?
Tomato
## Footnote
Berries have an entire fleshy pericarp with multiple seeds.
80
What defines a drupe?
One large seed (pit) inside a hard endocarp
## Footnote
Examples include cherries, peaches, and almonds.
81
What are simple fruits?
Fruits that develop from one ovary
## Footnote
Examples include berries, legumes, and drupes.
82
What are aggregate fruits?
Fruits that develop from multiple ovaries in one flower
## Footnote
Examples include strawberries and blackberries.
83
What are multiple fruits?
Fruits that develop from multiple flowers
## Footnote
Examples include pineapple and jackfruit.
84
What are accessory fruits?
Fruits that develop from non-ovary tissue like the receptacle
## Footnote
Examples include apples and strawberries.
85
What distinguishes fruits from vegetables?
Fruits develop from flowers; vegetables come from vegetative parts
## Footnote
Botanically, tomatoes and cucumbers are fruits, while broccoli and carrots are vegetables.
86
Fill in the blank: __________ develop from flowers.
Fruits
87
Fill in the blank: __________ are fleshy and many-seeded.
Berries
88
True or False: Vegetables develop from flowers.
False
## Footnote
Vegetables come from vegetative parts of the plant.
89
What is a study tip for memorizing fruit types?
Use flashcards and mnemonics
## Footnote
Examples include "Berry = fleshy & many-seeded".
90
Where does the food source in a gymnosperm (pine) seed come from?
The megagametophyte (haploid, n). Forms before fertilization.
91
Where does the food source in an angiosperm (flowering plant) seed come from?
The triploid endosperm (3n). Forms after fertilization.
92
Why are angiosperms more efficient than gymnosperms?
They only make the food source after fertilization, avoiding wasted energy.
93
How long does fertilization take in gymnosperms vs. angiosperms?
Gymnosperms: ~1 year ⏳
Angiosperms: Hours to 1 day ⏩
94
What are the two transport systems in plants?
1️⃣ Xylem – Moves water & minerals UP (roots → leaves).
2️⃣ Phloem – Moves sugars & hormones BOTH WAYS (leaves ↔ roots).
95
What is transpiration?
Evaporation of water from leaves → Pulls water up through xylem.
96
What forces help water move up the xylem?
✅ Cohesion – Water sticks to itself.
✅ Adhesion – Water sticks to xylem walls.
✅ Tension – Evaporation pulls water up.
97
What is osmosis?
Water moves from low solute to high solute concentration.
98
How does water move in a plant?
From HIGH water potential (Ψ) to LOW water potential (Ψ).
99
What happens in a hypotonic (low solute) solution?
Water enters the cell, making it turgid (firm & swollen).
100
What happens in a hypertonic (high solute) solution?
Water leaves the cell, causing plasmolysis (wilting/shrinkage).
101
What are the types of transport across plant cell membranes?
1️⃣ Passive Transport (No Energy Needed)
Simple Diffusion (Oxygen)
Facilitated Diffusion (via channels, e.g., aquaporins for water)
2️⃣ Active Transport (ATP Needed)
Proton Pump – Moves H⁺ out of the cell, requiring energy.
Cotransport (Symport) – H⁺ moves in, bringing sucrose in against its gradient.
102
What is facilitated diffusion?
Passive transport using channel proteins (e.g., aquaporins for water).
103
How does active transport work?
Uses ATP to move molecules against their gradient (low → high).
104
What is water potential (Ψ)?
Water’s ability to move & do work, measured in megapascals (MPa).
105
What factors affect water potential?
1️⃣ Solute potential (Ψs) – More solutes = lower Ψ.
2️⃣ Pressure potential (Ψp) – More pressure = higher Ψ.
106
How does water potential affect movement?
Water moves from HIGH Ψ to LOW Ψ.
107
What are the two main parts of a plant body?
Root system (anchors, absorbs water/ions) & Shoot system (stems, leaves, flowers; supports photosynthesis & reproduction).
108
What are the components of a vegetative shoot?
Internode, node, leaf, axillary bud (excludes reproductive structures).
109
What is a node?
A point on the stem where leaves, branches, or flowers grow.
110
What is an internode?
The stem segment between two nodes.
111
What is an apical bud?
A bud at the tip of a stem or branch; responsible for vertical growth.
112
What is an axillary bud?
A bud in the axil of a leaf that can grow into a branch or flower.
113
What is a stipule?
A small leaf-like appendage at the base of a leaf stalk.
114
What is a petiole?
The stalk that connects a leaf to the stem.
115
What three characteristics define plant cell types?
1. Size of vacuoles, 2. Whether they are alive at maturity, 3. Thickness of cell walls.
116
What is the primary cell wall?
The first, thinner layer of a plant cell’s wall.
117
What is the secondary cell wall?
A thicker, stronger layer inside the primary cell wall, providing additional support.
118
What are the three main tissue types in plants?
1. Dermal tissue (protection), 2. Ground tissue (storage, photosynthesis, support), 3. Vascular tissue (transport).
119
What is the function of meristems?
They allow plants to grow continuously by producing new cells.
120
What are the two main types of meristems?
1. Apical meristem (responsible for primary growth – height).
2. Lateral meristem (responsible for secondary growth – girth).
121
What are the two types of lateral meristem?
✅ 1. Vascular cambium (adds xylem & phloem).
✅ 2. Cork cambium (produces outer bark).
122
What is primary growth?
Growth in height (occurs at apical meristems).
123
What is secondary growth?
Growth in girth (occurs at lateral meristems).
124
Do monocots undergo secondary growth?
No, most monocots lack secondary growth.
125
What is the function of dermal tissue?
It forms the outer protective layer of the plant.
126
What is the epidermis?
The outermost, usually one-cell-thick layer of dermal tissue.
127
What is the cuticle?
A waxy layer that reduces water loss from stems and leaves.
128
What are the three specialized dermal cells?
✅ 1. Guard cells (control stomata).
✅ 2. Trichomes (hair-like structures for protection & reduced evaporation).
✅ 3. Root hairs (increase surface area for water absorption).
129
What are the three types of ground tissue cells?
✅ 1. Parenchyma (storage, photosynthesis, secretion; living cells).
✅ 2. Collenchyma (flexible support; living cells).
✅ 3. Sclerenchyma (rigid support; dead at maturity).
130
What is the function of xylem?
It transports water & minerals from roots to leaves (one direction).
131
What are the two types of xylem cells?
✅ 1. Tracheids (long, narrow, found in all vascular plants, less efficient).
✅ 2. Vessel elements (shorter, wider, found in angiosperms, more efficient).
132
What is the function of phloem?
It transports sugars, hormones, and amino acids (both directions).
133
What are the two types of phloem cells?
✅ 1. Sieve cells (found in gymnosperms, less efficient).
✅ 2. Sieve-tube members (found in angiosperms, more efficient).
134
What is the role of companion cells in phloem?
✅ They support sieve-tube members, which lack a nucleus
