Bio Exam Mats 2

Nerds (im updating this as i go). When i ask for an example, it can be any example of the sort. It does not have to be identical to the written example

What type of plant is Angiosperm?

Flowering Plants

What are the 3 stages of an angiosperm plant life cycle? (the 3 Fs)

Flowering

Fertilization

Fruits

What is a Sporophyte and define its life cycle

Definition

• Diploid phase of the plant

Life cycle

• Multicellular diploid form from union of gametes (fertilization)

• Sporophyte produces haploid spores (which eventually turn into female gametophyte) via meiosis

Why does sporophyte undergo meiosis?

To produce spores

What do plants do with the spores that they make from meiosis?

It divides the spores via mitosis and make gametes

Define Fertilization

When diploid zygote form new sporophyte

Name and define 2 parts of the flower

• Reproductive shoot

  • Reproductive part of flower

• Determinate shoot

  • Stops the flower from growing after a certain length

What are the 4 organs of a flower?

1. Sepals

2. Pedals

3. Stamens

4. Carpels

What is the function of the stamen and carpel?

Reproduction

What is the function of Sepals?

It hovers over and protects the floral bud before it opens

What is the function of Petal?

Gives flower its unique color

Define Stamen

Reproductive organ that contains stalk and anther

What is an anther?

Top part of stamen that contains male gametophyte

• this is where pollen is produced

Define carpel

Reproductive organ that contains ovary, stigma, and style.

Define Style

Neck of the carpel

Where is the ovary located?

At the base of the carpel

Define Stigma

Sticky structure at the top of the style

True or False: It is still a complete flower regardless if it has all 4 organs

False: A complete flower requires the presence of all 4 organs

(Carpel, Pedal, Sepal, and Stamen)

True or False: The flower is still incomplete even when one of its organ is missing

True

How many pollen sac does each anther have?

4

True or False: A pollen sac contains 4 microspores

True

Each microspore undergoes _______ to produce pollen grain (sperm)

Each microspore undergoes mitosis to produce pollen grain (sperm)

What does pollen grain contain? (2 things)

A generative cell and a tube cell

True or False: The pollen grain was made from the carpel and move to the stamen to be fertilized

False: The pollen grain was made from the stamen and move to the carpel to be fertilized

What do pollen grain do after they reached the stigma?

Tube cell within the pollen grain produces pollen tube that deliver the sperm to the carpel (where the female gametophyte is located)

How many sperms are delivered to the carpel?

2

Describe the process of the development of the male gametophyte

1. Each anther has 4 pollen sacs

2. Each sac produces 4 microspores via meiosis

3. Each microspores undergo mitosis and produce generative cell and tube cell (pollen grain)

True or false: The male gametophyte was transferred to the sepal after it produces the pollen grain

False: The male gametophyte was transferred to the carpel after it produces the pollen grain

Describe the process of female gametophyte

• One megasporocyte the ovule undergoes meiosis and produces 4 haploid megaspores

• Megaspores undergoes mitosis and form 8 haploid nuclei (the embryonic sac)

• The ovule becomes the seed

True or False: Ovary becomes the fruit and ovule becomes the seed

True

Fill in the Blank (Embryonic Sac structure edition): Click on the picture

Click on the picture to check your answer

One end of the embryonic sac contains an egg cell and 2 cells. What are these 2 cells called?

Synergids

What is the function of synergids cells?

To attract and guide pollen tube

Define Polar nuclei

• The 2 nuclei located in the center of the embryonic sac

• Shared a cytoplasm

What locate at the opposite end of the synergids?

3 (antipodal cells) cells with unknown function

Define Pollination

Transfer of pollen from one anther to another stigma

How does plant compensate for the inefficiency of wind pollination?

By making a large amount of pollen

Aside from the wind, what other factors pollinate the plants? What attracts the pollinators to the flower?

Bees - They are attracted to bright color flowers

Moths, butterflies, flies, bats, and birds - Attracted by odor

Describe the process of double fertilization

• 2 sperms are directed to the ovary through the pollen tube by GABA (gamma-aminobutyric acid)

• 1 sperm fertilize the egg, form zygote, produce concetrated Ca2+ to prevent the another sperm from entering the zygote

• 1 combines with 2 polar nuclei and form endosperm (food storing tissues of the seed)

What is the function of the endosperm?

Provide nutrients for the seed

Where do monocot and dicot seed store their nutrient?

Monocot - they store their nutrient in the endosperm

Dicot - They transfer the nutrient from the endosperm into the cotyledon

What is cotyledon?

The first part of the dicot seed that is above the ground.

How many cotyledon does monocots and dicots have?

Monocot - 1

Dicot - 2

What does hypocotyl attach to in the seed?

It attaches to the root (the radicle)

What does the epicotyl attach to in the seed?

It attaches to the first leaves

Describe the maturation state of the seed

Seed dehydrate itself

Seed coat harden to trap the nutrient inside the seed

Describe seed dormancy

Seed will not germinate until it meet its environmental requirement to germinate

Example:

• Some seed requires heavy rainfall to germinate

What is imbibition and why does seed relies on it to germinate?

Imbibition is the hydration of the seed

• (Just know that the seed take in water because the inside has low water potential and water likes to go from high to low)

Seed relies on imbibition to expand and rupture the seed coat

Explain the germination stage of the seed

• Imbibition: Seed receives enough hydration, start to expand, and seed coat ruptures

• Enzymes began to digest the nutrient and transfers them to the embryo

• The embryonic root (the radicle) forms first and shoots the seed upward

• Hypocotyl straighten, and raises the cotyledon and the epicotyl, as it responds to light

• Epicotyl spread its first leaves and start to perform photosynthesis

• The cotyledon breaks off of the epicotyl after all the nutrient is used

True or false: Fruits are developed from the ovary

True

What is the requirement for the development of fruit?

Pollination

• Without pollination, fruit cannot be able to develop

What is simple fruit?

Fruit that develop from 1 carpel

What is aggregate fruit?

Fruit develop from more than 1 carpel and forms fruitlets.

• An example is raspberry

What are the two mechanisms for the asexual reproduction of plants? Describe the mechanism

Fragmentation

• Separation of a parent plant that develops into a whole plant

• An example: Severed stem develops root

Apomixis

• Asexual reproduction of seeds

• An example: Dandelions

What are some of the advantages and disadvantages of asexual reproduction

Advantages

• Does not require pollinators

• Can clone itself if it is well adapted to its envrionment

Disadvantages

• Greater risk of extinction because they all have the same genes

What are some advantages and disadvantages of sexual reproduction

Advantages

• Genetic variation (able to adjust environmental changes

Disadvantages

• Relies on pollinator

• Exposed to predators

What is self-fertilization and why does plant prevent itself from doing it?

Self-fertilization - Plants fertilize itself

Plants prevent itself from fertilizing to ensure genetic diversity

How do plants prevent self-feritilization?

• Some flower lacks either the carpels or the stamen

• The maturity rate of the stamen and carpel is different

• Self-incompatibility (Prevents the growth of pollen tube)

What is plant breeding

Humans cross-breeding plants to obtain the desired trait

Define the 2 meanings of plant bio tech and give an example for each

• Innovation in the use of plants

  • Weaving monocots leaf into hat

• The use of genetically modified organism

  • increase crop yield

Define transgenic and give an example

GM organism that is genetically modified to express another species’ genes

• Corns can secrete BT that is lethal to insects

What are the 3 pros of GM plants?

• GM plants can increase

  • Food yields and reduces world hunger

  • Improves nutritional value

• The use of GM can reduce the green house gases

  • GM plants can absorbs more efficiently

What are the 2 cons of GM plants?

• Unknown risk to humans such as decreaseallergens exposure to insecticides

• Transgenic genes can cause herbicide resistant

What is Etiolation?

Plant sprout regardless of the presence of light

What is De-etiolation?

Formation of shoots and leafes due to the presence of light

Name at least 1 example of de-etiolation

• Stem elongation slows

• Root elongation

• Leaf expands

• Shoot produces chlorophyll

What is the process of the signal transduction pathway?

1. Reception

   1. Receptor receives stimulus (a signal)

2. Transduction

   1. Second messenger activated and amplifies the signal within the cell

3. Response (2 types of response)

   1. In transcriptional regulation

      1. Protein binds to a part of DNA and control the production of certain genes

   2. In post-translational modification

      1. Alters the proteins and changes its activity

What is the light receptor that involve in de-etiolation called?

Phytochrome

Describe the process of the transduction pathway in de-etiolation

1. Light hits the phytochrome (light receptor)

2. Phytochrome changes its shape

3. The shape change causes cyclic GMP (cGMP) and Ca2+ level to increase

4. cGMP activates protein kinases which phosphorylates proteins and other enzymes

Define phototropism

Growth of shoots towards or away from the light

What did Darwin and his son observe regarding phototropism?

• Grass tends to bend towards the light only if the tip of the grass is present.

• If the tip is cut off, the grass does not curve towards the light

• Darwin concluded that the tip of the grass is responsible for sensing light

Describe a hypothesis that was made after Darwin’s grass observation

Asymmetrical distribution of auxin causes the darker side of the grass to grow faster than the side that faces the light

Describe Auxin and identify its function and location

• Growth hormone

• Function

  • Stimulates cell growth and cell elongation

  • Inhibit axillary growth

• Location

  • Apical meristem in both shoot and root

• Influence by phototropism and gravitropism

Name (at least) 1 consequence of having too much and too little of Auxin

• Too much

  • No axillary growth

    • Axillary buds on the shoot and root cannot grow

• Too little

  • Apical meristems in shoot and root can’t elongate.

    • 2 consequences

      • Root can’t elongate to find water and mineral

      • Shoot can’t elongate and result in being shaded by the surrounding plants

Describe cytokinins and identify its function and location

• Axillary growth hormone

• Function

  • Signals the growth of axillary buds

  • Slows the deterioration of the leaves

• Location

  • Produced in actively growing tissues such as fruits, roots, and embryos

Name (at least) 1 consequence of having too much and too little of Cytokinins

• Too much

  • There will be more of photosynthesis and less of glucose production because there will be a lot of chlorophyll in the leaf

• Too little of

  • There will be less chlorophyl pigment and reduces photosynthesis efficiency

Describe gibberellins and identify its function and location

• Growth hormone

• Function

  • Stimulate stem and leaf growth

  • Work with auxin to stimulate stem elongation and formation of fruits

  • Break seed dormancy

• Location

  • Apical buds

  • Apical roots

  • Young leaves

  • Seeds

Name (at least) 1 consequence of having too much and too little of gibberellins

• Too much

  • Over-sized fruit production

• Too little

  • Stem don’t elongate much

  • Fruit infertility

Describe ABA (abscisic acid) and identify its function and location

• Hormone that regulate growth

• Function

  • Slows down growth (growth control)

  • Inhibit seed germination

  • Gives seeds the ability to withstand dehydration

• Location

  • ABA can be found in all plant cells

Name (at least) 1 consequence of having too much and too little of ABA

• Too much

  • Plant will die because over accumulation of ABA in the leaf can cause the stomata too close

  • Seed will not germinate

• Too little

  • No growth control; plant will grow uncontrollably

  • Seed will suffer hydration

Describe ethylene and identify its function and location

• Ripening hormones

• Function

  • Ripen fruits

  • Thickens stem

  • Cell destruction

    • Example: leaf during the fall

      • Less auxin makes ethylene more effective

        • Breaking down the green chlorophyll and exposes the red pigment in the leaf

  • Leaf abscissions

    • Aging of the leaf

• Location

  • Made by most plant cells

Name (at least) 1 consequence of having too much and too little of Ethylene

• Too much

  • Kills the plant internally

  • Premature ripening in fruits

• Too less

  • Plants die under stress condition

True or False: Ripening of the fruit caused by ethylene is a form of negative feedback

False: Ripening of the fruit caused by ethylene is a form of positive feedback

Define Circadian rhythm

Cycle that is controlled by environmental variable such as light

What enable plants to measure the passage of day and night?

Phytochrome

Give an example of short day plant

Poinstattias

Give an example of long day plant

Radishes

Define Gravitropism and which hormone participate in this

Plant growth in response to gravity

• Shoot moves upward

• Root moves downward

How does statoliths, auxin, and gravity play a role in root growth

• Statolith aggregate at the bottom of the cells in the root cap (due to gravity) and stimulates auxin

• Auxin stimulates the elongation of root cell and helps it move downward

Define thigmomorphogenesis and give an example.

Definition

• Changes in plant occur due to mechanical influence

Example

• Rubbing young plants will cause them to be shorter

Define thigmotropism and provide an example

Plant growth in response to touch

• Example: Vine will grow straight until it found something to latch onto

How do plant respond to drought?

ABA clogged up in the stomata preventing it from open

• Plant can slow down transpiration and conserve water this way

  • The downside is photosynthesis is reduce

How dos\ plants respond to flooding?

They secrete ethylene into the cortex of the root, killing the cell there to create air space for O2 to diffuse

How do plants respond to cold stress

Plants produces sugar to

• Help prevent water loss

• Slows down the freezing of the cell

What is Metabolic Rate and how do we measure them?

Definition:

• The amount of energy required for chemical reaction to occur

We can measure the metabolic rate by measuring:

• Rate of heat loss

• Rate of O2 consumed

• Rate of CO2 produced

Define the 2 bioenergetic strategies

Endothermic

• Body temperature s regulated within organism

• The heat is generated by metabolism

Ectothermic

• Has to regulate heat via external source

  • Ex:

    • Snake warm its body by sunbathing on top of a rock

    • Snake cool its body by hiding in the shade

What is the relationship between body size and metabolic rate?

They have an inverse relationship

• The smaller the animal, the more calories requirement (and vice versa)

Why does a rat burn more calories than an elephant?

The rat has more surface to volume ratio that generate a great amount of heat

What is the consequence of burning more calories

Higher heart rate

Higher breathing rate

Define Basal Metabolic Rate (BMR)

Amount of calories you need to maintain function

• Can measure when an adult endotherm is at rest