General Biology Exam 2 Review

23,24

Describe how the stomata and the cuticle helped plants to adapt to land.

Being on land required plants to evolve mechanisms to minimize dehydration, move water and nutrients against gravity, and damage from UV radiation:

• A waxy covering called a cuticle protects most land plants from desiccation (the cuticle covers exposed surfaces and is relatively impermeable)

• Small openings, called stomata, are found mostly on the underside of leaves and allow for gas exchange between the plant and the environment.

What is transpiration?

Is the evaporation of water through the stomata.

In the alternation of generations life cycle, what are gametophytes? Sporophytes?

All land plants exhibit alternation of generations:

• Plants alternate between a multicellular haploid (n) phase and a multicellular diploid (2n) phase

• Multicellular haploid individuals are called gametophytes

Sporophytes?

• Multicellular diploid individuals

• Sporophytes produce spores by meiosis within a structure called the sporangium.

What is produced in the Archegonium?

Egg (female gamete)

What is produced in the Antheridium?

Sperm (male gamete)

In early plants like moss, which generation is dominant? In all other plants (ferns, seed plants), which generation is dominant?

• Early land plants like moss → Gametophyte is dominant

• Ferns, pine trees, flowering plants → Sporophyte is dominant.

What are examples of nonvascular plants? Were they the first to evolve?

Mosses, liverworts, hornworts, and certain algae. Yes, they were the first plants to evolve and colonize land.

What do bryophytes require to reproduce?

Water. That’s because their sperm must swim through water to reach the egg.

How are vascular plants such as ferns different from mosses? Why are they better adapted to life on land?

They have roots and vascular tissue that transport water and nutrients, allowing them to grow much taller and dominate the land.

Compare xylem and phloem

Xylem conducts water and dissolved minerals up from the roots.

Phloem

conducts sucrose and other organic compounds throughout the plants

The large megaphylls (leaves) of the fern are called ______. Clusters of sporangia on the underside are called ______.

fonds ;sori

In ferns, how does fertilization occur?

Sperm swim from the antheridium to the archegonium, where fertilization occurs.

What are seed plants?

Seed plants are vascular plants that use seeds during the dispersal phase of their life cycle.

What are the parts of a seed?

Sporophyte embryo, stored food, and protective seed coat.

How does the pollen get carried to the female gametophyte in seed plants?

By wind or animals such as birds and insects.

What are the 2 groups of seed plants? How are they similar? Different?

Gymnosperms and angiosperms. Both are seed plants that have vascular tissue.

• Gymnosperms: ovules are not completely enclosed by sporophyte tissue at pollination.

• Angiosperms: ovules are completely enclosed in the ovary, which becomes a fruit.

Give examples of gymnosperms and their uses.

Conifers, cycads, ginkgoes, and gnetophytes. Conifers are the most plentiful group. Gymnosperms have “naked” seeds that are not enclosed by fruit.

Give examples of angiosperms.

Fruits, vegetables, nuts, herbs, and grains; flowering plants such as duckweed and Eucalyptus.

How are the 2 classes of angiosperms derived?

• Monocots — one cotyledon (seed leaf)

• Eudicots — two cotyledons (seed leaves)

Compare the characteristics of monocots to dicots. (cotyledons, veins in leaves, flower parts)

• Monocots: 1 cotyledon, parallel veins, flower parts in 3s, fibrous roots, scattered bundles in the stem

• Eudicots: 2 cotyledons, netted veins, flower parts in 4s/5s, taproot, vascular bundles in a ring

Know the parts of a flower. Which ones are male and female?

• Male = Stamens: filament + anther

• Female = Carpels: stigma + style + ovary

• Ovule → seed

• Ovary → fruit

What part of the flower does the fruit come from

The ovary becomes the fruit.

What is double fertilization?

One sperm unites with an egg to form a diploid zygote, while the other sperm unites with the polar nuclei to form a triploid endosperm nucleus.