Ren R 121 - Quiz 1 flashcards

Prokaryotic cells

Cells without nuclei (Bacteria)

Eurayotic cells

Cells with nuclei (Animals and higher plants)

What are the differences in features between Eukaryotes and Prokaryotes?

Nucleus: Present in Eukaryotes with nuclear membrane, absent in Prokaryotes

Organelles: Membrane bound in Eukaryotes, absent in Prokaryotes

Cell size: Large (10-100 micrometers) in Eukaryotes, small in prokaryotes (1-5 micrometers)

Cell wall: Present in both Eukaryotes and Prokaryotes

Higher plant:

Plants that have well developed vascular tissues (Xylem and phloem)

Eg: Ferns and relatives, Gymnosperms, angiosperms

Lower plants

Typically lack vascular tissues, but may have underdeveloped vascular systems (algae, mosses, and liverworts)

Why is Cell size important?

• A surface:volume ratio dictates how easy it is to absorb things and get them to the organelles → Nucleus regulates all parts of the cell activity

  • Large cells exchange materials less efficiently and require more time for signals to travel within it

  • Smaller cells have a higher surface area:Volume ratio making it easier to transport things and communicate

Cell wall

• Surrounds and protects the protoplasm within the cell, and in plants give them their structure

  • Most abundant and diverse structure on earth (used for food, fuel, and shelter in production)

Protoplasm

Consists of all the living components of a cell

Plasma membrane

The membrane that binds all living components in the cell

Cytoplasm

All cellular components between the plasma membrane and the nucleus

Cytosol

The souplike fluid inside the cytoplasm that all the organelles are dispersed in

Organelles

A Structures with various shapes and size, with specialized function in the cell (they are not required to have a membrane)

Cytoplasm vs Protoplasm difference

• Cytoplasm: All the contents inside the cell membrane, excluding the nucleus 

• Protoplasm: INcludes the cytoplasm and the nucleus

The cell wall is important to the cell because

• It maintains the cell shape

• It controls cell expansion

• It protects the delicate cell contents within

• Regulates transportation

• Stores food reserves

What are the main components of plant cell walls?

Main thing is carbohydrates

• Main components: Cellulose, hemicellulose, and pectins

• Additional components: Varying amounts of lignin, and small amounts of proteins and minerals

Pectins

Concentrated in the middle lamella and primary wall, where they help bind adjacent cells together and gives the material a more jelly like feel

Cellulose

• Made from glucose monomers in long chains

Hemicellulose

Gluelike substance that holds cellulose fibrils together

Glycoproteins

Proteins with sugars associated with their molecules

Middle lamella

Made from a layer of pectin produced when the new cell walls are formed, usually shared by two adjacent cells

Secondary cell walls

• Derived from the primary walls by thickening and including lignin, and produced on the inside of the primary walls

  • Plant cells are designed to have a lot of structure, softer species don’t have a 2nd cel wall

  • Made from more cellulose (40-80%) than the primary walls

  • Walls thicken as the cell ages, until it takes up a larger volume of space

  • Reinforced by lignin while it’s forming

Which cells have thin walls?

Cells that manufacturer, process, or store food

Which cells have thicker walls

Cells involved in support

Plasmodesmata

• Fluids and dissolved substances can pass through primary walls to adjacent cells 

  • Smaller things can pass through more efficiently 

  • Tiny strands of cytoplasm that extend between the cell walls allows nutrients and water to be exchanged

Middle lamella:

Most cell walls are permeable and allows for slower movement of water dissolved substance between cells

Plasma membrane

Outer boundary of the living part of the cell (inside of the cell wall)

Functions of the plasma membrane

• Regulates the movement of substances in and out of the cell, and is selectively permeable

• Responsible for the production and assembly of cellulose for the cell walls (puts it into the walls)

Plasma membrane composition

• Has two layers of Phospholipids, with phosphorus heads pointing out, and lipid tails pointing in

• Protein channels that are used for diffusion and expelling things across both boundaries (either partially or fully through the membrane)

• Carbohydrates that are linked to the lipids and proteins

Are phosphate heads hydrophilic or hydrophobic?

hydroPHILIC (love water)

Are lipid tails hydrophilic or hydrophobic?

Lipid tails are HydroPHOBIC (hate water)

Why does the bilayer of phospholipids make for a more stable cell

by only allowing non-polar cells to diffuse through

Why does the phospholipid bilayer have two tails, one straight and one bent? what are they made of?

• Plasma membrane needs to be able to adapt to different environments, because damage to the plasma membrane means death for the cell by regulating for different temperatures

• Straight tail made from Saturated fatty acids

• Bent tail made from unsaturated fatty acids

Peripheral proteins

Proteins in the plasma membrane are Peripheral proteins, and integral proteins

Nucleus

• The control center of the cell which provides DNA with information to fulfill all the cells needs

  • Helps with growth, differentiation, and making new organelles

  • Stores hereditary information that gets passed from cell to cell when a new cell is formed

The Nucelus is made of

• Nuclear envelope

• Nuclear pores

• Nucleoplasm

• Nucleoli

• Chromatin

Nuclear envelope

Two membranes that are a phospholipid bilayer

Nuclear pores

Occupy one third of the total surface area of the envelope and allow certain molecules to pass from the nucleus to the cytoplasm

Eg: Proteins carried into the nucleus, and RNA carried out of the nucleus

Nucleoplasm

Granular looking fluid filled with short fibers and suspending several different larger bodies (including the nucleoli)

Nucleoli

The large nuclear bodies that are made from RNA and other proteins

Chromatin

Made from DNA, when the nucleus divides the chromatin become condensed and are then called chromosomes

Chromosomes

• Every cell for an animal or plant species has a fixed number and composition of chromosomes

  • During sexual reproduction half the number goes into the pull with the other half of the chromosomes coming for the second parent

Endoplasmic reticulum

A network of flattened sacs and tubes that create channels through the cytoplasm, and are connected to the outer membrane of the nucleus

What is the purpose of the endoplasmic reticulum? What are the two types?

• Facilitates cellular communication

• Rough ER: Covered with lots of Ribosomes on the outer surface, and used for synthesis, secretion, and/or the storage of proteins

• Smooth ER: Has very few ribosomes (if any) lining the surface, and is for lipid secretion

• Smooth ER and Rough ER both synthesize enzymes that are involved in cellular respiration, and appear at the primary site of membrane synthesis

Ribosomes

• Small, spherical organelles that are floating in the cytoplasm or attached to membranes

  • Made from RNA and proteins subunits which are assembled within the nucleolus, released and then, with special RNA molecules, initiate protein synthesis

  • Don’t have a membrane so may or may not be counted as organelles

Dictyosomes and functions

Stacks of flattened discs/vesicles that are scattered throughout the cytoplasm of a cell

Bound by branching tubules from the Endoplasmic reticulum, but aren’t directly connected to it

Functions: Modifies CHOs attached to proteins that are synthesized and packaged in the endoplasmic reticulum, assembles complex polysaccharides and collects them in small vesicles

Golgi Apparatus

A group of Dictyosomes that are collected together

Plastids

• Double-membrane bound organelles that are responsible for manufacturing and storing essential food and pigments

  • Develop form the proplastids

Proplastids

Pale green or colourless organelles that are about the same size as the mitochondria, and are simpler in internal structure than plastids with fewer thylakoids

Chloroplasts

• The most common plastid found in plant cells, being present in all  green tissues, particularly leaves

  • Responsible for photosynthesis

  • Made from an aqueous matrix called the stroma, containing the thylakoid membranes in folded sacks called grana (collective name)

Thylakoid membranes

Flattened tubes where clusters of chlorophyll and carotenoid pigments are embedded next to the enzyme complexes in the Chlorplasts

Key Chloroplast information is:

• The nucleus dictates most of the activities in the chloroplast

• Chloroplasts have DNA molecules that are encoded to produce certain proteins needed for photosynthesis

• Chloroplasts contain RNA (messenger) and ribosomes (make proteins) for protein synthesis

Chromoplasts

• Yellow, orange, or red in pigment due to the synthesis and accumulation of carotenoid pigments 

  • Develop from chloroplasts in certain cases by removing the chlorophyll

  • Most abundant in certain plants, with the purpose of attracting pollinators and seed spreaders

Leucoplasts and 3 types

The group of plastids that are all essentially colourless

• Amyloplasts: Synthesis and storage of starches, as well as sensing gravity to determine which way the roots should grow

• Elaioplasts: Synthesis and storage of oils

• Proteinoplasts: Storage of proteins

Mitochondria

Stores the energy released from cellular respiration, storing it in ATP, and then breaking the bonds to release the energy as needed

Key information about the Mitochondria

• Mitochondria are very small, and will be numerous in a cell

• They move around a lot and accumulate where energy is needed

• Mitochondria rearrange C skeletons and fatty acid chains allowing for a variety of organic molecules to be build

• Bound by two membranes, with the inner membrane folding numerous times to create cristae

• Matrix fluid contains DNA, RNA, ribosomes, proteins, and dissolved substances

Cristae

The fold created that increase the surface area available to the enzymes in the mitochondria

Microbodies and three types

Small, spherical organelles that contain specialized enzymes and are bound by a single membrane. They’re spread throughout the cytoplasm and are what gives it its granular appearance

Peroxisomes, Glyoxisomes, Lysosomes

Peroxisomes

Contains the enzymes needed by some plants to survive during hot conditions through photorespiration and are generally associated with the chloroplasts

Glyoxisomes

Contains enzymes that help turn fats into Carbohydrates (CHO), usually located near the mitochondria

Lysosomes

Stores enzymes that digest proteins and certain other large molecules but are confined to animal cells

Vacuoles

Filled with a watery fluid called cell sap, it maintains the cell pressure and pH, as well as storing cell metabolites and waste storage

• Crystals of waste products form within the cell sap once the ions have become concentrated there

• Vacuoles recycle certain materials in the cell and help to breakdown and digest organelles

Cell sap

Moderately acidic liquid found inside the vacuoles, which maintains the pressure of the cell and contains dissolved substances (eg: salts, sugars, organic acids, etc)

Cytoskeleton and what its made of

The outer layer (?) that helps the cell maintain its shape, even after being compressed. It’s involved in the movement and architecture of the cell, made from two types of fibers

Microtubules and Microfilaments

Microtubules

Made from proteins called tubulins, and control the addition of cellulose to the cell wall, as well as cell division, movement of cytoplasmic organelles, controlling the movement of vesicles, and moving the flagella and cilia possessed by some cells

Microfilaments

Plays a role in Cytoplasmic streaming

Cytoplasmic streaming

The movement of organelles as a current within the cytoplasm, carrying them around within the cell walls, and potentially facilitating the exchange of materials within a cell as well as from cell to celle

Gymnosperms

Naked seeds (not in an ovary) with male and female cones, using wind pollination

Angiosperm

• Enclosed seeds inside the ovary, male and female organs generally found in the same flower and coevolution with pollinators

  • Ovule is fertilized and develops into a seed inside a fleshy carpel (ovary)

Angiosperms are divided into two classes based on the number of seed leaves

• Monocotyledons (eg: corn)

• Dicotyledons (eg: beans)

What are the features of monocots?

• One seed leaf

• Parallel leaf veins

• Flower parts in 3s, or multiples of 3s

• Fibrous (adventitious) root stem

• Stem vascular bundles are scattered

• Pollen mostly monosulcate (single pore)

• Less than 10% are woody, largely associated with grasses

What are the features of dicots?

• Two seed leaves

• Netted leaf veins

• Flower parts in 4s and 5s

• Primary taproot

• Stem vascular bundles in a ring

• Pollen mostly tricolpate (three pores)

• More than 50% are woody

Dicots have plant bodies organized into above and below ground systems. What are these systems?

• Shoot system: The above ground system that includes the stems, leaves, buds, flowers, and fruits of a plant

• Root system: The below ground system that includes the roots

Meristem

The tissues that contain the actively dividing cells which are differentiated as they grow, classified based on the location on the plant

Apical Meristem

• The meristem that’s at the tip of the plant, which increases the shoot length 

  • In vegetative plants it may produce leaves

  • In reproductive plants it may produce flowers

Axillary Meristems

The meristem tissue between the leaf petiole and the stem, resulting in an axillary branch or flower

Lateral Meristems

Increases the plant girth through secondary growth

Intercalary Meristems

Increases the the internode length and only present in monocots

What are the two parts of a leaf?

Lamina (blade) and stalk (petiole)

Compound leaves

Compound leaves are leaves where there is only one petiole and node attachment point, but several leaflets growing from a rachis

Tap root

A root system that has a primary root with lateral roots branching from it

Root apical meristem

The primary meristem adding to the root length

Monocot vegetative shoot

• The shoot apex (apical meristem) is very close to the soil, protected and not obvious 

  • Leaves grown from the apical meristem are from nodes that are very close together

Grass leaves

•  Made from a blade and sheath, with an axial bud that can create a new branch (tiller)

  • Leaf formations are already present (though small) even while the plant is still very close to the ground

Tiller

The basic unit of a grass plant, coming from the axillary buds and is a clone of the parent plant

Fibrous root system

The root system used by monocots where the initial seminal root system is replaced with an adventitious root system coming from the node at the base of the plant

Monocot reproduction

•  Apical meristem stops making leaves and puts all its energy into forming the flowering structure

• 2. Internodes elongate to push the flower higher up on the true stalk/culm

Vascular cambium and which meristem is it in?

Lateral meristem

Produces additional tissues, the secondary xylem and secondary phloem

Cork cambium and which meristem its in

Lateral meristem

Produces the outer bark in woody species

Secondary growth

• The lateral growth that occurs in plants after the completion of primary growth (aka height growth)

Tissues and 2 types

• Groups of cells that are structurally or functionally distinct from what's around them, made from differentiated meristematic cells

  • Simple tissues: Only one type of cell

  • Complex Tissues: Made from two or more types of cells

Apical meristem creates three primary meristem tissues:

• Protoderm: Dermal tissue (plant skin)

• Procambium: Vascular tissues (circulatory system)

• Ground tissues: All tissues that are neither dermal nor vascular (Plant muscle and fat) and is the simple tissue

Ground tissues and types

Responsible for metabolism, storage and support, and are broken down into three types

• Parenchyma

• Collenchyma

• Schlerenchyma

Parenchyma

Made from parenchyma cells it’s the most abundant cell type, with thin walls and large vacuoles used for storage of starch grains, oils, etc

Parenchyma features and function

• Parenchyma cells are living at maturity and capable of cell division, generally with only a primary wall but are capable of regeneration and wound healing, as well as initiating adventitious structures

  • Functions: Photosynthesis, storage, and secretion

  • Function: The repair tissue via cell division

Aerenchyma

A special parenchyma cell that has lost of air space between the cells, allowing for more plant buoyancy and generally found in aquatic and wetland plants

Chlorenchyma

Parenchyma cells contain numerous chloroplasts, with their main focus being photosynthesis

Collenchyma cells

• Cells with a living cytoplasm that stay alive for longer. Generally have thick and uneven cells due to the extra primary wall growing in the corners

  • Usually right below the epidermis and providing flexible support

  • Note: strings of celery are Collenchyma

Sclerenchyma and types

Cells with thick, tough secondary walls full of lignin. Dead at maturity and mainly used in support

Sclereids

• AKA stone cells are reduced sclerenchyma cells with very thickened lignified walls which may be randomly distributed through tissues (eg: grittiness in pears) or in fruit pits

  • Not very flexible and is just for support

Fibers

• Cells found in various different tissues such as roots, stems, leaves, and fruits. Usually longer then they are wide and have a small cavity or lumen in the cell centre

  • Important economic value as they are used for making fiber, and other goods