Biology 10 quiz 2 Flashcards
what are multicellular advantages
- larger size organism (SA:V)
- variety of specialized cells can perform more complex tasks
- ability to adapt to and thrive in many different environments
multicellular organization:
cells -> Tissues -> Organs -> Systems
cells
smallest basic unit of life
tissues
cluster of cells sharing the same structure and function
organs:
combination of different tissues that work together to perform a specific function
system
combination of organs and tissues that perform a complex function
Plant organization:
plants are specialized into two systems:
- shoot system
- root system
they are further specialized into 3 different tissues:
- dermal tissue
- ground tissue
- vascular tissue
shoot system:
everything above ground (eg. stems, leaves, flowers, fruit, buds)
root system:
everything below ground (eg. roots)
dermal tissue:
- also called epidermis
- outer layer of cells that covers all non-woody plants
- important for gas exchange and water and mineral uptake from soil
what is epidermis mean
“skin”
ground tissue:
- the majority of the plant
- functions: stem for strength and support, roots for food and water storage, leaves where photosynthesis occurs
Vascular tissue:
- important in plant transport
has xylem and phloem
xylem:
-moves water and dissolved minerals from soil to leaves for photosynthesis
- dead hollow cells consisting only of cell walls
- linked end to end, forming long tubes called xylem vessels also known as tracheids
phloem:
-moves sugars produced from photosynthesis from leaves to the rest of the plant
- made of living sieve tube cells joined end to end making continuous ducts called phloem vessels
- controlled by the companion cells
cell specialization in leaves:
leaves contain several types of specialized cells that help with their most important activity photosynthesis
what do all organisms need to function?
energy
where does energy come from and pass down too?
it comes from the sun and is passed down through the food chain
how to do organisms create photosynthesis and cellular respiration
organisms convert suns energy into usable energy throu two important chemical reactions, photosynthesis and cellular respiration
photosynthesis:
-requires light
- light energy is converted into glucose
photosynthesis equation
carvon dioxide + water + light energy -> glucose + oxygen
6CO2 + 6H2O + Energy -> C6H12O6 + 6O2
why does photosynthesis occur only in plants
they have chloroplasts which contain chlorophyll -> traps the suns energy for the reaction
cellular respiration:
- second reaction converts glucose into usable ATP energy
- reaction occurs in the mitochondria in both plant and animal cells
How do photosynthesis and cellular respiration work together
-the two reactions are interdependent
- photosynthesis makes glucose and cellular respiration converts it into usable energy
- animals don’t have chloroplasts so we consume plants to get glucose
Gas exchange in plants
plants use their leaves to exchange gases with the environment
how plants breathe
- air diffuses through the stomata
- CO2 in air dissolves into H2O around cells
- water enters the leaf through the xylem - O2 passes out of cells into air spaces and then through the stomata
-H2O vapour also exits through the stomata(plants try to prevent this from happening)
whats the stomata
an opening in the plant leaf that allows gases to pass through
what do woody plants use for gas exchange
woody plants use lenticels
whats transpiration
-the evaporation of water from leaves
- can cause plants to lose 99 % of the water absorbed by roots
what are guard cells
-guard cells change shape to allow stomata to open or close
-controls the amount of gas exchange and transpiration
how do guard cells control the stomata?
- opening and closing of the stomata is controlled by H2O in guard cells (moves in and out through osmosis)
- H2O moving in creates high turgor pressure forcing stomata open
- stomata close as the amount of H2O in guard cells decreases from transpiration
When doe the stomata and gaurd cells open
most plants open the stomata during the day and close at night to maximize photosynthesis and reduce water loss
control mechanisms of the stomata
- The number of stomata in a plant depends on its environment
-dry = don’t want to lose water = fewer stomata
- humid = water loss inst an issue = many stomata
Vascular system
-series of interconnected tubes to transport H2O, minerals and glucose throughout the plant
- extends from roots through the stems to the leaves
- consists of xylem and phloem
water uptake in roots
H2O and minerals enter plants from roots via osmosis and active transport
root hairs increase SA:V for more efficient absorption of minerals and water
in what kind of organism does water need to be transported over much longer distances
multicellular organisms
what helps transport H2O over large distances
The polarity of water. H2O molecules are polar so they can cling to each other and to other substances
what is cohesion
attraction of H2O molecules to other H2O molecules
- tendency to stick together
- + end of one is attracted to - end of other
what is adhesion
tendency of H2O molecules to stick to other surfaces
how does water move in a plant?
root pressure pushes and transpiration pulls
how does root pressure move water
-root pressure pushes water up
-as minerals build up, more H2O moves into the root
- pressure builds up and forces fluid up xylem (helped by cohesion and adhesion)
how does transpiration move water?
-transpiration pulls
- evaporation of H2O through stomata creates a pulling force