bio paper 1

light microscope

passes a beam of light in lenses to form an image in a object

what is the magnification of a light microscope

x2000

what can it be used for?

viewing living objects

electron microscopes

use beams of electrons, rather than light, to produce images

what is the magnification of electron microscopes

x2000000

resolving power

a measure of the clarity of an image

equation of magnification

Magnification = size of image / size of object

what features does an animal cell have

Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes

what feature does a plant cell have?

cell wall, cell membrane, mitochondria, vacuole, chloroplast, nucleus

nucleus

Control center of the cell

cytoplasm

A jellylike fluid inside the cell in which chemical reaction occur.

cell membrane

A cell structure that controls which substances can enter or leave the cell.

Mitochondria

energy is transferred during respiration

ribosomes

site of protein synthesis

Vacuole

contains cell sap which keeps the cell rigid and supports the plant

cell wall

A rigid layer that surrounds the cells of plants

chloroplast

Site of photosynthesis

Eukaryotic cell

they have a cell membrane, cytoplasm and a nucleus that contains chromosomes, which is made by a genetic material called DNA

examples of eukaryotic cells

plants, animals, fungi, protists

prokaryotic cell

cell that has a cell wall, cell membrane and cytoplasm but no nucleus

examples of prokaryotic cells

bacterial cells

plasmids

small DNA molecules that replicate separately from the bacterial chromosome

flagella

whiplike tails found in one-celled organisms to aid in movement

specialised cells

Cells that are adapted to carry out a particular function

what happens as a organism develops

Cells differentiate to form different types of cells

example of specialised cells

Sperm cells, nerve cells, muscle cells, root hair cells

nerve cells

fast cell communication, sends impulses through nervous system

dendrites

receive messages from other cells

axon

carry the impulses from one place to another

synapses

pass impulses to other cells by producing transmitter chemicals

muscle cells

causes movement of the body. They move the skeleton, heart, and internal organs

smooth muscle cells

found in tissue in the digestive system and contract to move food along the gut

features of muscle cells

• special protein that slide over each other

• many mitochondria to transfer energy needed for chemical reaction

• stores glycogen that can be used for respiration

sperm cells

they are specialised to move swim through the female reproductive system to reach the egg

features of sperm cells

long tail, lots of mitochondria for energy, enzymes to digest egg cell membrane

examples of specialised plant cells

root hair cells, xylem cells, phloem cells

root hair cells

growing tip of a plant root that increase the surface area available for the absorption of water and minerals from the soil.

Features of root hair cells

• large vacuole that speeds up the water movement by osmosis

• have many mitochondria so it can transfer energy for active transport of mineral ions

photosynthetic cells

• contains chloroplasts

• collects energy from the sun to make food

photosynthetic cells features:

• has chloroplast to trap light needed for photosynthesis

• often found in continuous layers of leaf and the outer layer of the stem

• vacuole to keep it rigid

xylem cells

cells in plants that transport water from roots to leaves (upward direction) and supports the plant

ligin

strengthens cell walls in water conducting cells.

phloem

The vascular tissue through which food moves in some plants by photosynthesis

sieve plates

broken down cell walls that are between the phloem cells

how are phloem cells kept alive?

companion cells

companion cells

contain mitochondria that transfer energy to aid movement of dissolved food in the phloem

diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

concentration gradient

difference in concentration between two areas

How is the rate of diffusion affected?

Concentration gradient, temperature, surface area

examples of diffusion

• oxygen and glucose diffused into the cells of the body for respiration

• carbon dioxide into actively photosynthesising plant cells

osmosis

diffusion of water across a selectively permeable membrane

how does osmosis move

from a high water concentration to a low water concentration

isotonic

Having the same solute concentration as another solution.

hypertonic

Having a higher concentration of solute than another solution.

hypotonic

solution that is more dilute

what happens if animal cells are surrounded by hypotonic solution

it will swell and burst because the water is moves into the cell by osmosis

what happens if animal cell is surrounded by hypertonic solution

water moves out of the cell and shrinks

how should animals avoid bursting or shrinking

you need a complex mechanisms to control the concentration

how does turgor pressure occurs

no more water can enter a cell due to the pressure

how to maintain turgor pressure

• hypotonic water keeps the cell rigid

• plant cells in a hypertonic solution lose water and become flaccid so plants wilt

plasmoysis

• water leaves the cell

• vacuole and cytoplasm

• membrane gets pulled away from the cell

turgor pressure

• water moves into plant cell to make osmosis

• vacuole swells

• cytoplasm gets pressed by the cell wall

• cell leaves and stems become rigid

osmometer

instrument for measuring osmotic pressure

Investigating osmosis experiment:

rectangular potato is placed into different sugar or salt solutions to see if the mass changes before and after.

active transport

moves molecules against a concentration gradient form a lower to higher concentration

What does active transport require?

Energy from respiration

cystic fibrosis

thick sticky mucus because active transport systemin their mucus cells is not functioning

examples of active transport

root hair cells absorbs mineral ions from the dilute solution by active transport

Small organisms have a _ surface area to volume ratio.

large

single celled organisms

tiny but can gain enough of material such as oxygen

exchange surfaces

• large surface area

• thin membrane

• short diffusion path

ventilated

movement of air into and out of the lungs

gaseous exchange surfaces in animals must be ----------?

ventilated

villi in small intestine

• large surface area

• short diffusion path

• good blood supply

Gills in fish

Have a large surface area for oxygen absorption due to the presence of gill arches and filaments.

operculum

• act as a pump to maintain flow of water over the gills.

• blood carrys oxygen away to maintain concentration gradient

in the lungs where is oxygen absorbed

alveoli

why do plants have long thin roots

Increase surface area for water absorption.

stomata

Small openings on the underside of a leaf that allows gases in and out of the leaves.

what is SA:V

surface area to volume ratio

what reaction is photosynthesis?

endothermic reaction

how is photosynthesis carried

green plants an algae

symbol equation of photosynthesis

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

Word equation for photosynthesis

Carbon dioxide + water -> glucose + oxygen

how is photosynthesis an endothermic reaction

energy is transferred from the environment to the chloroplasts by light

process of photosynthesis

carbon dioxide in take in and water is taken up to the roots

process number two for photosynthesis

chlorophyll traps light energy for photosynthesis

process number three for photosynthesis

energy is used to convert carbon dioxide and water into glucose and oxygen

how is leaves well adapted for photosynthesis

broad and flat and thin so diffusion path is small

guard cell opens stomata so gases can diffuse

veins contain xylem which brings water to the leaves and phloem take glucose away

what happens if there is lack of light for photosynthesis

slows the rate down because light transfers energy for the process

what happens if its cold for photosynthesis

enzymes do not work effectively which slows down the rate

what happens if there is limited carbon dioxide

rate of photosynthesis is slow

limiting factor

factor that causes the growth of a population to decrease

variegating leaf

less photosynthetic activity

light intensity and rate of photosynthesis practical:

count bubbles of oxygen per min

collect total volume of oxygen

if light source is near rate of photosynthesis increases

if light source the rate decreases

light intensity equation

1/distance^2

uses of soluble glucose

respiration, produce fats and oils, produce cellulose to strengthen the cell

examples of carnivore plants

Venus fly trap

Venus fly trap

collects insects due to low nitrogen in soil

more a plant photosynthesises

the more biomass it makes and the faster it grows