Plant Science Exam 2

What are phytohormones?

Naturally occurring plant chemicals required in small amounts that regulate growth and development.

Where is auxin primarily produced?

Apical meristems, young leaves, buds, and developing fruits.

What is the main effect of auxin on cells?

Stimulates cell elongation.

What causes phototropism?

IAA accumulation on the shaded side, causing greater cell elongation there.

What is positive gravitropism?

Roots bending downward in response to gravity.

What hormone promotes seed germination and breaks dormancy?

Gibberellins (GA)

What are gibberellins synthesized?

Shoot apex, young leaves, embryos, fruit tissue, and roots.

What is the primary function of cytokinins?

Stimulate cell division.

How do cytokinins affect apical dominance?

They reduce apical dominance by promoting lateral bud growth.

What hormone promotes fruit ripening?

Ehtylene

What is the triple response caused by ethylene?

Inhibited stem elongation, thickened stem, and horizontal growth.

What hormone stimulates stomatal closure during drought?

Abscisic Acid (ABA)

What is the role of ABA in seeds?

Promotes seed dormancy and prevents premature germination.

Which hormone pair works together to regulate cell division?

Auxin and cytokinin

What triggers bolting in biennial plants?

Gibberellins, often stimulated by heat, cold, or drought.

Who is considered the father of modern genetics?

Gregor Mendel

What organism did Mendel use for his genetic experiments?

Garden Peas

What is a pure line in genetics?

A line that consistently produces offspring with the same trait when self-pollinated.

What is the F1 generation?

The first filial generation resulting from a cross between two pure parents.

what phenotypic ratio did Mendel observe in the F2 generation of monohybrid crosses?

3:1

What does the principle of dominance state?

One allele can mask the expression of another.

What does the law of segregation describe?

Alleles separate during gamete formation.

What phenotypic ratio is expected in a dihybrid cross?

9:3:3:1

What is incomplete dominance?

A form of inheritance where the heterozygote shows an intermediate phenotype.

What is an example of multiple alleles in humans?

ABO blood type

What is polygenic inheritance?

A trait controlled by multiple genes with additive effects.

What is apomixis?

Asexual see formation producing genetically identical offspring.

What is a scion in grafting?

The upper part of a graft that becomes the shoot system.

What is a rootstock?

The lower part of the graft that provides the root system.

What propagation method uses long shoots bent into the soil?

Simple layering

What does the central dogma describe?

The flow of genetic information from DNA to RNA to protein.

What process creates mRNA from a DNA template?

Transcription

What process uses mRNA to build a protein?

Translation

Which RNA base pairs with adenine in DNA?

Uracil

What is a codon?

A three-nucleotide sequence on mRNA that codes for an amino acid.

What is a start codon?

AUG

What molecule carries amino acids to the ribosome?

tRNA

What are the two major components of a ribosome?

Large and small ribosomal subunits.

What is a gene?

A DNA sequence that codes for a specific protein.

What is an allele?

Different forms of a gene.

What is the purpose of mitosis?

To produce two genetically identical daughter cells.

During which phase do chromosomes line up at the metaphase plate?

Metaphase

During which phase do sister chromatids separate?

Anaphase

What structure forms during cytokinesis in plant cells?

A cell plate

How many haploid cells result from meiosis?

Four

Plant cells contain some structures that are unique to plant cells and are not found in animal cells, these structures include?

Cell wall, chloroplast, vacuole

Photosynthesis takes place in the _________ (organelle) and respiration takes place in the ________ (organelle).

chloroplast, mitocondria

Lateral meristems area located in the stem and allow the plant to becomre larger in girth, apical meristems are located in ____ and ____ and increase the plants lenghth.

 

Root tips and shoot tips

The function of the cell wall is to?

 

Provide support, protection and shape

Intercalary meristems are found?

At the base of Monocot leaves

A type of tissue that consists of a single layer of cells on the exterior of stems, leaves, flowers, and fruits is called the ?

Epidermis

The three types of permanent ground tissues are?

Parenchyma, collenchyma, sclerenchyma

This vascular tissue moves soluble sugars, proteins, hormones and salts from the leaves to other parts of the plant.

Phloem

What vascular tissue is characterized by sieve cells and companion cells

Phloem

This vascular tissue contains sclerenchyma cells that form treachids, fibers, and vessels?

Xylem

Which of the following is statements about root growth are true?

All of the above

In a plant root, root hairs occur in the _______ region?

 

Zone of differentiation or maturation

A bud that occurs in a non-normal place on the plant is termed a _____
bud?

Adventious

An underground, enlarged, food storing stem covered with papery leaves is called a _______________?

Corm (Papery leaves)

Monocot stems are characterized by which of the following?

 

Scattered vascular bundles

Most plant cells are/have ____ chromosomes

Diploid

What is the role of Auxin?

Helps plants grow upward and form roots. Tells the top of the plant to stay in charge.

What is the role of Cytokinin?

Encourages branching and leaf growth. Balances auxin.

What is the role of Gibberellin?

Makes plants taller, helps seeds sprout, and promotes flowering.

What is the role of Abscisic Acid?

The stress hormone. Helps plants survive drought by closing stomata. Keeps seeds dormant.

What is the role of Ethylene?

The ripening hormone. Also helps plants respond to damage or crowding.

What is a simple fruit?

One ovary, one flower (tomato, peach, apple, corn

What is an aggregate fruit?

One flower and many ovaries (strawberry + raspberry)

What is a multiple fruit?

Many flowers fused (Pineapple + fig)

What is an accessory fruit?

Includes non-ovary tissues (Apple, strawberry)