Botany Unit 1

Rainforests: why are they important?

They are important because they home 50% of all living species.

Rainforests: what is deforestation?

Deforestation is massive clearing of forests and land.

Why are rainforests being cleared? How much longer will they last?

They are being cleared for lumber and are predicted to only last another 40 years at this rate.

What are some impacts humans have on the environment?

Drained water, added pollutants to water and air, deforestation, used pesticides, and cleared natural vegetation.

What is environmental impact?

An impact that directly affects the environment

What are the ways to reduce negative effects humans have on the earth?

Replace pesticides with biological pest control, recycle, render pollutants harmless before disposal, and change agricultural practices.

What is biomass?

The collective dry weight of organisms.

What is aerobic organisms?

An organism that uses oxygen

What do plants do that make them so beneficial to humans

They produce oxygen and decrease carbon dioxide

How long would animal life exist on earth without plants?

11 years

Plants are sources of multiple produces of human society: explain why and give various examples

They are an alternative fuel source through fossil fuels, plants produce medicines, food, clothing, and more

What is fossil fuel?

Remains of dead plants and animals that are reduced with heat and pressure, and end up making burnable carbon

What are alternate energy sources?

Other options for fuel/energy

What is Botany? Who are botanists?

Botany is the study of plants, while botanists are those who study plants.

What is the scientific method?

Describes the process of developing and testing a hypothesis

What is a hypothesis?

A tentative and unproven explanation of an observation

What does it mean to have a valid experiment?

It can be recreated

What are variables?

The aspects of an experiment that are tested and controlled

What is data?

Results from the experiment

What is a principle and a theory?

A principle is a generalization derived from experimental data, and a theory is a generalization derived from a cultivation of principles.

Plant Physiology

Plant functions

Plant Anatomy

internal structure of plants

Plant Taxonomy

describes names and classifies plants

Plant Geography

deals with plant distribution

Plant Ecology

studies the interaction between plants and their environment

Plant Morphology

the form and structure of plants

Genetics

the science of heredity

Cytology

studies cell structure and function

Economic Botany and Ethnobotany

the practical uses of plants and plant products

Who discovered cells?

Robert Hooke

What is cell theory

the scientific theory that all cells are composed of cells and cells form a unifying structural base of organelles

Who discovered the nucleus? When?

Robert Brown, in 1831

What is spontaneous generation? Who finally disproved it?

The idea that all living things just spontaneously appear and that life just appears

What are light microscopes?

are microscopes which increases magnification using light and are generally made of glass and or crystal

What are the two types of light microscopes and what are they used for? Which can magnify at a greater power?

the two types of light microscopes are compound ( distinguishes organelles 2 micrometers or larger in diameter) and dissecting ( allows 3 dimensional viewing) microscopes. The compound microscope magnifies at a greater amount, magnifying up to 1500x where the dissecting microscope magnifies 30x.

What are electron microscopes?

use a beam of electrons produced by high-voltage electricity passing through a wire

What are two types of electron microscopes and how are they different?

The two types are transmission and scanning, the main difference being how transmission electron microscopes are used for showing inside material and scanning electron microscopes show the outer material.

What is the difference between a prokaryotic cell and eukaryotic cell?

having a nucleus, prokaryotic cells lack a nucleus while eukaryotic cells contain them

What is protoplasm?

the liquid containing all living cell components

What are the components of cytoplasm?

cytosol ( fluid containing organelles ) and organelles

What are organelles?

structures of various shapes and sizes with specialized functions who are usually connected to membranes.

Why is a cell being small an advantage?

they can effectively communicate with all parts of the cell and surface area

What is glucose?

C6H12O6 is carbohydrates ( sugar) it’s the primary source of energy in the cells of all living things

What is the structure of a plant cell wall? What is it mostly made of? What are some additional components of the cell wall matrix?

The structure of a plant cell wall is primarily cellulose ( long chains of glucose monomers ) and than hemicellulose ( a glue-like substance that holds together fibrils) pectin ( helps give stiffness like jelly), and glycoproteins ( proteins who have sugars associated with their molecules )

What is the middle lamella? What’s inside it?

produced when new cell walls are produced. It’s shared by two adjacent cells and a layer of pectin

Describe the location and details for the primary and secondary walls of the cell

The primary walls are flexible and form on either side of the middle lamella.

Secondary walls are produced inside the primary walls, they are derived from the primary walls by thickening and including lignin which is rigid, structural material. Cellulose microfibrils are embedded in lignin for strength like steel rods in concrete.

What are plasmodesmata?

cytoplasmic strands that extend between cells through small openings

Plasma Membrane

the semipermeable outer boundary of a living part of the cell. It regulates the movement of substances in and out of the cell. It’s composed of phospholipids arranged in two layers with proteins interspersed throughout.

Phospholipid bilayer and fluid mosaic model

The phospholipid bilayer is when two phospholipids attach to each other so the heads are both outward with the tails inward to protect each from their respective weakness or need.

The fluid mosaic model is the culmination of those phospholipids joining and creating the phospholipid bilayer and than proteins attach and move around freely

Nucleus

the control center of the cell and contains DNA

It sends coded messages from DNA to be used amongst the cell, while being bound by two membranes which make the nuclear envelope. Within the nuclear envelope are channels called nuclear pores, which permit only certain molecules to pass from the nucleus to cytoplasm. Then the fluid inside the nucleus is called nucleoplasm, which contains nucleoli composed of RNA, and chromatin which is composed of DNA and proteins that can coil and become chromosomes.

Endoplasmic reticulum ( rough and smooth )

A network of flattened sacs and tubes that form channels throughout the cytoplasm.

It facilitates cellular communication and channeling of materials along with synthesising membranes for other organelles and modifies proteins. There are two types, rough and smooth Endoplasmic reticulum. Smooth ER makes fats and don’t have ribosomes on them, where rough ER has ribosomes on the outside actually making them rough and those make proteins.

Ribosomes

consists of two subunits that are composed of RNA and proteins

They link amino acids to construct complex proteins. They occur on the outside of rough ER or in cytoplasm, chloroplasts or other organelles.

Dictyosomes and vesicles

stacks of flattened disks or vesicles that collect, package, and deliver information within the cell.

Dictyosomes modify carbohydrates attached to proteins that are made and packaged in the ER. They also assemble polysaccharides and collect them in small vesicles.

vesicles are sacs pinched off of dictyosomes, that migrate to plasma membrane, fuse with it, and secrete contents outside the cell.

Plastids

An organelle that stores or manufactures carbohydrates

There are multiple types of plastids. Chloroplasts are the most conspicuous, they’re green because of chlorophyll and are bound by double membrane. They contain grana made of thylakoids which their membranes contain chlorophyll and is where the first steps of photosynthesis occur. Then chloroplasts have stroma which is colorless fluid containing enzymes. And finally, they contain DNA molecules.

Then there’s chromoplasts that synthesize and accumulate carotenoids ( yellow, orange, and red pigments )

Finally there’s leucoplasts that are colorless and synthesize starches

Mitochondria

Releases energy produced from cellular respiration

The mitochondria produces energy within a cell. It’s bound by two membranes, the inward membrane forms numerous folds called cristae, which increase surface area available to enzymes in matrix. The matrix also includes DNA and RNA. ATP ( Adenosine Triphosphate) is the cells energy currency.

Microbodies

Small, spherical bodies distributed throughout the cytoplasm that contain specialized enzymes.

enzymes are proteins that break/create bonds and allow chemical reactions to occur at a faster rate. Microbodies are bound by a single membrane. They include Peroxisomes that contain enzymes that assist in photorespiration ( plants take up oxygen ) and Glyoxysomes that contain enzymes that help in conversion of fat to carbohydrates.

Lysomes store enzymes that digest proteins and other molecules in animal cells Can take up t

Vacuoles

Can take up to 90% of the volume in mature cells. Bonded by vacuolar membranes called tonoplasts. Vacuoles are filled with watery fluid called cell-sap. Cell-sap contains dissolved substances like salts, sugars, organic acids, and small proteins, it also frequently contains water-soluble pigments called anthocyanins ( red, blue, purple). Cell-saps purpose is to maintain cell pressure and pH, storage of numerous cell metabolites and waste products cell-sap is also moderately acidic.

Cytoskeleton

Involved in movement within cell and in cell’s architecture

they have a network of microtubules and microfilaments. Microtubules control addition of cellulose to cell wall, are involved in movement of flagella and cilia, are found in fibers of spindles in dividing cells, and are thin, hollow, and tubelike, while being composed of tubulins (proteins). Microfilaments role in cytoplasmic streaming, which is the movement of cytoplasm so that cells can move.

What is the cell cycle?

an orderly series of events when cells divide. It’s divided into interphase and mitosis

What is interphase?

the period when cells aren’t divided, the preparation

What are the three parts of interphase and what happens in each?

G1, S, and G2

G1 cells increase in size, then during S DNA replication takes place, leading to G2 when the mitochondria and other organelles divide, and microtubules are produced.

What is mitosis? What does it produce?

The process of cellular division, and it produces two identical daughter cells with equal amounts of DNA and other substances

Prophase

chromosomes condense by coiling and tightening to become shorter and thicker. Chromosomes made of two identical chromatids are held together by centromers. Within that process kinetochore ( protein complex) is located on the outer surface of each centromere, and spindle fibers ( microtubules) become attached to the kinetochore and anchored to the two poles of the cell. This leads to the nuclear envelope dissociating and the nucleolus dissolving.

Metaphase

chromosomes align between the poles around the circumference of the spindle at the cell’s equator, by the end centromers hold each sister chromatid separate lengthwise.

Anaphase

sister chromatids separate and are pulled to opposite poles, with centromers leading the way. Chromatids after separation are called daughter chromosomes.

Telophase

each daughter chromosome get surrounded by a nuclear envelope. Daughter chromosomes become longer, thinner, and eventually indistinguishable. Nucleoli reappear, spindle fibers disintegrate, and the cell plate forms at the equator.

How does a cell plate form?

phragmoplasts ( a complex of microtubules and ER) develops between daughter cell nuclei, microtubules trap dictyosome derived vesicles, vesicles fuse to form cell plate, cell plate grows outward toward mother cell wall, and portions of ER are trapped between vesicles, forming plasmodesmata

Similarities and differences of animal cells and plant cells.

Where plants have cell walls, animals have internal or external skeletons. Plants have cell plates and plasmodesmata but animals have their cells divided by pinching in two. Animals also have a plasma membrane called cell membrane, and centrioles present during cell division. While plants have plastids and vacuoles.

Where does mitosis occur in plants?

meristems which are areas of a plant where new cells are created, like the tip of roots