Botany

__ levels of carbon dioxide help keep the earth cool

Decreased

Conifers (gymnosperms) __ ___ produce flowers

Do not

How are fungi similar to plants?

Immobile and produce spores

How are fungi different from plants?

Differ in biochemistry and genetics

all plants have a _______ ____

scientific name

An individual plant is the ________ result of the interaction of genes andenvironment

Temporary

Organisms reproduce and have __________ offspring whosefeatures pass to more offspring

non-identical

Evolution by natural selection is a model consistent with

▪ Observations of natural organisms ▪ Experiments ▪ Theoretical considerations

Life on Earth began about 3.5 billion years ago with ________

prokaryotes

Prokaryotes lack ______

nuclei

Photosynthesis arose 2.8 billion years ago in a __________

cyanobacteria

Organelles evolved, facilitating division of labor and specialization

▪ DNA became located in its own organelle, the cell nucleus .▪ Eukaryotes (plants, fungi, animals, algae) have nuclei and other membrane-boundorganelles.

Eukaryotes diversified, some gaining mitochondria and some gainingchloroplasts (via endosymbiosis).

▪ Those with mitochondria evolved into protozoans, fungi, and animals. ▪ Those with mitochondria and chloroplasts evolved into plants and algae.

Some modern groups have derived (apomorphic) features

▪Features that evolved from an ancestral feature

There are several alternative adaptations to cope with different environments.

▪ Ex., Leaf loss in autumn vs. shoot-system die-off with persistent subterranean bulbs tocope with freezing winters

Overview of plant structure

▪ Stems ▪ Leaves ▪ Branches ▪ Roots

Roots, stems, and leaves

▪ Leaves harvest energy from the sun and package it into the sugar called glucose. ▪ Roots obtain minerals and other nutrients .▪ Stems bear leaves.

Vegetative organs obtain energy and materials for growth and survival, but donot carry out ______ ______

sexual reproduction

Almost all stems bear leavesthat are attached at regions called ___

nodes

_______ ___ just above thenodes, can become branches or flowers.

Axillary buds

Flowers have:

▪ Carpels (pistils) that contain one or more ovules. The three main parts of a carpel are the stigma, style, andovary. The stigma is where pollination occurs. ▪ Stamens that produce pollen ▪ Petals that attract pollinators ▪ Sepals that protect the flower

Carpels consist of three parts

▪ Stigma ▪ Style ▪ Ovary

Vascular tissues

▪ Xylem ▪ Phloem

Xylem

▪ Transports water and minerals upward from roots to all aerial parts

Phloem

▪ Carries sugars and various organic compounds as well as minerals and water throughout the plant.

Herbs have only the _______ ______ produced by cells at the tips of stems androots

primary body

Woody plants undergo secondary growth

▪ Possess a secondary meristem, the vascular cambium ▪ Produce secondary xylem (wood) and secondary phloem (bark)

photosynthesis equation

6CO2 + 6H2O --> light energy --> C6H12O6 + 6O2

Messenger RNA distributes _________ in the cell

Information

Plants perceive information from the environment in the form of:

▪ Light ▪ Temperature ▪ Seasonal changes ▪ Except at the equator ▪ Gravity

Photosynthetic Eukaryotes

▪ Algae [red algae, brown algae, green algae, others] ▪ Plants [also called true plants, land plants, or embryophytes] ▪ Plants without vascular tissue [mosses, liverworts, hornworts only] ▪ Plants with vascular tissues [vascular plants] ▪ Plants without seeds [vascular cryptogams] ▪ Lycophytes [often called "fern allies"] ▪ Ferns ▪ Plants with seeds [spermatophytes] ▪ Cycads (seed plants that typically have a stout and woody trunk ▪ Gingko (species of gymnosperm) ▪ Gnetophytes (gymnospermous vascular plants) ▪ Conifers ▪ Angiosperms ▪ Basal angiosperms [several groups] ▪ Monocots ▪ Eudicots

▪ Grades

Based on the level to which a group has evolved

Clades

▪ An ancestor and all its descendants ▪ The ancestors of any clade of any living organism lived in the past.

Neutralism

Neither species benefits or is harmed

Mutualism

A relationship between two species in which both species benefit

Predation

An interaction in which one organism kills another for food.

Commensalism

one organism benefits, whereas the other is neither harmed nor helped.

Amensalism

one organism harms another without receiving any benefit itself

Competition

both organisms harm each other.

Co-evolution

▪ Allows certain plants and animals to become well adapted to each other

Hemiparasites have chlorophyll and produce at least part of their own glucose

▪ Obtain water, minerals from hosts

Holoparasites do not have chlorophyll and do not photosynthesize.

▪ Most are subterranean. ▪ Seedling roots invade host roots and obtain what they need to survive.

Unicellular organism

An organism made up of one cell.

Multicellular organism

Organism made up of many cells

Negative consequence of division of labor

damage to part of the organism may lead to death of all cells

Membranes perform many important tasks in cell metabolism.

▪ Regulate the passage of molecules into and out of cells and organelles ▪ Divide the cell into numerous compartments, each with its own specialized function ▪ Act as surfaces that hold enzymes

Intrinsic proteins

at least partially immersed in the lipid bilayer.

Extrinsic proteins

are located outside themembrane.

In the fluid mosaic membrane

some proteins diffuse laterally and others arebound to adjacent proteins.

Facilitated diffusion

movement of charged substances is assisted by large intrinsic proteins that span the membrane

Active transport

molecular pumps bind to a molecule on one side of themembrane, change shape, and release the molecule on the other side; thisrequires energy.

Protoplasm

▪ Mass of proteins, lipids, nucleic acids, and water within a cell ▪ Includes organelles but not the cell wall

Plasma membrane

▪ Selectively permeable membrane that covers the protoplasm ▪ Located inside of the cell wall

The nucleus holds nucleoplasm

consisting of DNA, enzymes, histoneproteins, RNA, and water

The central vacuole has a single membrane, the tonoplast

▪ Stores water, salts, crystals, starch, protein bodies, and other granules ▪ Critical for cell enlargement ▪ Recycles monomers by taking in old,impaired organelles and using digestiveenzymes to break them down

Mitochondria

▪ Site of cellular respiration ▪ Double-membraned organelle with an outer and inner membrane ▪ Inner membrane folds to form cristae increasing surface area. ▪ Have circular DNA resembling that of prokaryotes. ▪ Can divide or enlarge as needed .▪ Adenosine triphosphate (ATP) generation

plastids

▪ Have an inner and outer membrane and an inner fluid called stroma .▪ Includes chloroplasts ▪ Diverse metabolisms take place in other plastid classes. ▪ Contain circular DNA resembling that of prokaryotes

Chloroplast

▪ Responsible for photosynthesis and contain the green pigment chlorophyll ▪ Double membraned ▪ Membrane sheets called thylakoids ▪ Stacks of thylakoids called grana ▪ Inner fluid called stroma

Amyloplast

▪ Starch-storing plastids. ▪ Occur in nonphotosynthetic areas of the plant.

Other Plastids

▪ Chromoplasts store bright lipid pigments found in some fruits and flowers. ▪ Leucoplasts are large, unpigmented plastids involved in fat and lipid synthesis. ▪ Phytoferritin is a plant protein attached to stored iron that is almost exclusivelystored in plastids

Ribosome

▪ Site of protein synthesis ▪ Occur in the cytoplasm and rough ER ▪ Are aggregates of 3 molecules of ribosomal RNA and ~50 types of protein ▪ Bound together by messenger RNA, forming a cluster called a polysome

Endoplasmic Reticulum

▪ ER is a system of narrow tubes and sheets of membrane within the cytoplasm .▪ Important in both manufacture and transport of molecules ▪ Two forms ▪ Rough (covered with ribosomes) ▪ Smooth (involved in lipid synthesis and membrane assembly)

Dictyosomes

▪ Stacks of thin vesicles heldtogether in an array thatprocesses materials to besecreted ▪ Forming face where ERvesicles accumulate ▪ Maturing face where vesiclesare released after the contentsare processed

Endomembrane system

consists of all the cell membranes except for the inner membranes of mitochondria and plastids

Cytosol

the clear substance of the cytoplasm and is composed of water,enzymes, and other chemicals.

Microbodies

▪ Small, spherical bodies that isolate reactions that produce or use hydrogen peroxide(H2O2). ▪ Peroxisomes detoxify by-products of photosynthesis. ▪ Glyoxysomes are involved in converting stored fats into sugars

Cytoskeleton

▪ Microtubules are structural elements of the cell that act as a "cytoskeleton." ▪ Means of motility for organelles and whole cells ▪ Composed of two types of protein with a globular tertiary structure: alpha-tubulin andbeta-tubulin ▪ Separate chromatids during cell division ▪ Cilia and flagella

Storage Products

▪ Plants store a variety of products .▪ Starch is sometimes converted into lipids and stored as large oil droplets .▪ Crystals of calcium oxalate or calcium carbonate ▪ Silica, tannins, or phenols ▪ Since there is no excretory mechanism, some of these products are simply stored waste

Cell wall

Primarily composed of: ▪ Cellulose ▪ Hemicellulose ▪ Pectins

Plant cells cannot communicate via direct physical contact.

▪ In plants the cell wall and middle lamella are a barrier. ▪ Plasmodesmata allow direct communication

Plasmodesmata are small channels that connect adjacent cells.

▪ Plasma membrane passes through them and creates a contiguous membrane fromcell to cell. ▪ A small stream of the cytosol and a section of the ER also pass through. ▪ Occur singly or in clusters called primary pit fields

Associations of Cells

▪ Plasmodesmata connect protoplasts to create the symplast. ▪ Many cells do not abut each other tightly, so there is intercellular space between. ▪ All intercellular space and cell walls together are called the apoplast. ▪ The symplast and apoplast together make up the entire plant

Cells in the growing points at the tips of roots and shoots never stop _______

dividing

Growth Phase of the Cell Cycle

The part of the cycle without division was named "interphase." Three phases can be detected during interphase. G1, S, and G2

During the G1 phase

The cell is recovering from division. It conducts most of its normal metabolism. Nucleotides are synthesized to be used for DNA replication

S phase (synthesis phase)

Genes in the nucleus are replicated. Thousands of genes are attached ina linear sequence forming achromosome. Histones complex with DNA andgive it both protection and structure. Entire chromosomes are replicatedduring S-phase.

During the G2 phase

Cells prepare for division. The α- and β-tubulins necessary for spindle microtubules are synthesized. The cell produces proteins for processing chromosomes and breaking down thenuclear envelope

Division of the nucleus is called

karyokinesis

Two types of karyokinesis

Mitosis: duplication division Meiosis: reduction division

prophase

Chromosomes condense by coiling. The nucleolus becomes invisible. The nuclear envelope breaks into vesicles.

Metaphase

Microtubules push and pull the chromosomes toward the cell center to form themetaphase plate. At the end of metaphase, an enzyme breaks down the connection between sisterchromatids

Anaphase

Spindle microtubules shorten and pull the separated sister chromatids toward oppositepoles of the cell.

Telophase

As the chromatids reach each pole of the cell, complete nuclear envelopes form andsurround each group of chromatids. Chromosomes uncondense. New nucleoli appear . Spindle depolymerizes and disappears

Cytokinesis

No matter how the protoplast divides, each half typically contains Mitochondria Plastids Endoplasmic reticulum (ER) Vacuoles During prophase, the preprophase band forms just inside the plasma membrane. Identifies the plane of division Marks the region where the new cell wall will attach to the existing wall

phragmoplast

set of short microtubules that forms in the center of the cell

The phragmoplast, vesicle, and walls are called

cell plate

Vacuole division is accomplished with a

phragmosome

phragmosome

Leptotene Zygotene Pachytene Diplotene Diakinesis

Leptotene

chromosomes begin to condense and become distinguishable but indistinct.

Zygotene

synapsis of homologs A structure, the synaptonemal complex, is present between the pairedhomologous chromosomes. A synapsed pair of homologous chromosomes is called a bivalent.

Pachytene

Chromosomes shorten and thicken. Crossing-over occurs between maternaland paternal homologs (involves thesynaptonemal complex). If the genes on the paternal and maternalchromosomes are slightly different, thenew chromosomes that result are slightlydifferent from the originals.

Diplotene

The homologous chromosomes move away from each other, but are held togetherby the centromeres. They are tangled together at points called chiasmata

Diakinesis

The homologs continue to separate. Chiasmata move toward ends until they become untangled. They are paired only at the centromeres.

In numerous tissues, karyokinesisoccurs without cytokinesis

Multinucleate cells are formed. Called coenocytes

Division is by binary fission

Circular DNA replicates attached to the cell membrane. The replicates are separated by membrane growth . Cytokinesis occurs by a process of infurrowing. Plasma membrane pulls inward and pinches in two

The increase in length of the shoot and the root is referred to as

primary growth

increase in thickness or girth of the plant.

Secondary growth

Apical meristem

▪ present at the apex of the root and shoot ▪ responsible for increasing the length of a plant's body.

Lateral meristem

▪ responsible for an increase in thickness or lateral growth of a plant body. The cambium and cork cambium are examples of such types of tissues in a plant body.

makes up much of the interior of a plant and carries out basic metabolic functions

Ground tissue