biology EOY

what is a enzyme

large proteins that catalyse (speed up) reactions. Enzymes are not changed in the reactions they catalyse.

what is a tissue

group of cells with similar structures and functions

what is an organ

group of tissues working together to perform a specific function

What is the function of the liver in digestion?

produces bile, which neutralises hydrochloric acid from

the stomach and emulsifies fat to form small droplets with a large surface area

what is the function of saliva in digestion?

lubrication to help swallowing – contains amylase to

break down starch

name three proteins produced in the pancreas

amylase, protease, lipase

why are enzymes described as specific?

each enzyme only catalyses a specific reaction, because

the active site only fits together with certain substrates

(like a lock and key)

describe the function of amylase

designed to break down starch into glucose

where is amylase produced?

salivary glands, pancreas, and small intestine

describe the function of proteases

to break down proteins into amino acids

where are proteases produced?

stomach, pancreas, and small intestine

describe the function of lipases

to break down lipids into fatty acids and glycerol

where are lipases produced?

pancreas and small intestine

What are two factors that affect the rate of activity

of an enzyme?

temprature and pH

what does denatured mean?

shape of an enzyme’s active site is changed by high

temperatures or an extreme pH, so it can no longer bind

with the substrate

describe the effect of temprature on enzyme activity

as temperature increases, rate of reaction increases

until it reaches the optimum for enzyme activity –

above this temperature enzyme activity decreases and

eventually stops

describe the effect of pH on enzyme activity

different enzymes have a different optimum pH at which

their activity is greatest – a pH much lower or higher

than this enzyme activity decreases and stops

why do different digestive systems have different optimum pH s?

Different parts of the digestive system have very

different pHs – the stomach is strongly acidic, and the

pH in the small intestine is close to neutral

what is an organ system?

a group of organs working together to perform a

specific function

what does the gall bladder do in digestion?

stores bile – bile is alkaline to neutralise hydrochloric acid from the stomach, and emulsifies fat to form small droplets with a large surface area.

what does the stomach do in digestion?

• churns food

• releases protease – digests proteins

• releases hydrochloric acid – kills pathogens

what happens in the small intestine?

digested food is absorbed into the blood

what happens in the large intestine?

water and minerals are absorbed into the blood

sites of production for amylase

salivary glands

pancreas

small intestine

sites of production for proteases

stomach

pancreas

small intestine

sites of production for lipases

pancreas

small intestine

effect of temprature on enzymes GRAPH

how doe enzymes work? (lock and key theory)

1) The enzyme’s active site (where the reaction occurs) is a specific shape.

2) The enzyme (the lock) will only catalyse a specific reaction because the substrate (the key) fits into its active site.

3) At the active site, enzymes can break molecules down into smaller ones or bind small molecules together to form larger ones.

4) When the products have been released, the enzyme’s active site can accept another substrate molecule

metabolism

the sum of all reactions taking place in your body

what nutrient does the benedicts test detect

sugars

what nutrient does iodine solution detect?

starch

what nutrient does the biuret reagent test detect?

protein

what nutrient does the ethanol test detect?

fats/lipids in solution

what colour change occurs in a positive iodine test

orange/brown to blue/black

what colour change occurs in a positive benedicts test?

blue to green/ orange/ brick red

what colour change occurs in a positive biurets test?

blue to purple

what colour change occurs in a positive ethanol test?

solution will turn cloudy

*memorise method for enzymes required practical*

*memorise method for enzymes required practical*

what substrate does amylase act on?

starch

what type of molecule is an enzyme?

a protein

in the enzyme required practical, what does the colour change of the iodine solution indicate?

blue black- starch still present

colourless- starch has been broken down by amylase

background info on enzymes required practical

The activity of biological catalysts (enzymes) are affected by pH. This practical explores how different pH levels affect the activity of amylase, an enzyme that breaks down starch into sugars. Using buffer solutions to alter pH, you will measure the rate of starch breakdown by observing changes in the colour of an iodine solution.

what is the purpose of labeling the test tubes with the pH of the solution in an experiment investigating the effect of pH on the rate of reaction of amylase enzyme?

to ensure the correct pH is added to the starch solution

what connects the stomach and small intestine?

duodenum

what is the role of bile?

• produced by the liver

• stored in the gallbladder

• bile will neutralise the contents of the stomach as it moves into the small intestine

• bile emulsifies fats- this increases the surface area of the fat droplets allowing lipase to be more efficient

how would you investigate the effect of temperature/ pH on the activity of amylase?

enzymes required practical (learn method)

how would you test for the presence of different nutrients in a food

food tests- e.g. benedicts, biurets, iodine, ethanol (learn methods)

what are carbohydrates made of?

units of sugars You can have simple carbohydrates (only the units of sugars) and complex carbohydrates (long chains of simple sugar units bonded together- starch/ fiber)

what are lipids made of?

three molecules of fatty acids joined to a molecule of glycerol

what are proteins made of ?

long chains of small units called amino acids

functions of proteins in the body

• structural components of tissues like muscles/ tendons

• responsible for hormones such as insulin

• antibodies which destroy pathogens as part of the immune system

• enzymes, which act as catalysts

function of lipids in the body

used in your body for cell membranes, hormones and the nervous system

function of carbohydrates in the body

Carbohydrates are the body's primary energy source, broken down into glucose for immediate energy in cellular respiration.

for animal, plant and bacterial cells, state whether they are eukaryotic or prokaryotic

name the five cell structures that are found in both animal and plant cells.

name the three cell structures that are found in plant cells but not in animal cells.

what is the role of the nucleus?

controls cell activity, contains genetic information.

what is the role of the cell membrane?

controls substances going in / out of the cell.

what is the role of the cytoplasm? (and what is it?)

it is a liquid gel and the site of most chemical reactions.

what is the role of mitochondria?

where aerobic respiration happens and energy is released.

what is the role of the ribosomes?

protein synthesis takes place, all proteins are made.

what is the role of the vacuole? (only found in plant cells)

place in cytoplasm filled with cell sap, gives cell structure.

what is the role of the cell wall? (only found in plant cells)

strengthens cell, gives it support, contains cellulose.

what is the role of chloroplasts? (only found in plant cells)

green, contain chlorophyll which absorbs light used for photosynthesis.

define diffusion

movement of particles from a high concentration to a low concentration.

where is the DNA stored in a eukaryotic vs prokaryotic cell?

eukaryotes: nucleus

prokaryotes: single loop of DNA

compare the size of eukaryotic and prokaryotic cells.

eukaryotes: large

prokaryotes: 1μ (very small)

compare the cell walls of eukaryotic and prokaryotic cells.

eukaryotes: made of cellulose

prokaryotes: peptidoglycan (not cellulose)

compare the number of cells of eukaryotic and prokaryotic cells.

eukaryotes: multicellular

prokaryotes: unicellular

define cell differentiation

the process by which cells become specialised

ROOT HAIR CELL

plant cell

function- designed for absorbing water and mineral ions from soil

adaptations- large surface area to help absorb water and minerals

PALISADE CELL

plant cell

function- designed for photosynthesis

adaptations- tall and have a large surface area

MUSCLE CELL

animal cell

function- contains proteins that contract

adaptations- many mitochondria to transfer energy

CILATED CELL

animal cell

function- line air passages in lungs, stop lung damage

adaptations- tiny hairs called cilia

SPERM CELL

animal cell

function- fertilise eggs

adaptations- enzymes on head and tail

PHLOEM CELL

plant cell

function- carry food around plant

adaptations- cell walls between cells

NERVE CELL

animal cell

function- to carry electrical impulses around the body

adaptations- long, thin, highly branched

RED BLOOD CELL

animal cell

function- to carry oxygen

adaptations- large surface area for o2 to pass through.

EGG CELL

animal cell

function- to be fertilised

adaptations- provides large food store

XYLEM CELL

plant cell

function- carries water and minerals to roots/ leaves

adaptations- lingrin supports plant

define resolution

“the degree to which it is possible to distinguish between two objects that are very close together. the higher the resolution, the greater detail you can see.”

define magnification

“how many times larger an image is that the actual object”

eyepiece lens

base

slide and clips

objective lens

stage

equation for magnification

magnification = image size

.                        actual size

how many μ (micrometers) in 1mm?

1 millimeter = 1000 μ (micrometers)

how many chromosomes do humans have?

46 chromosomes or 23 pairs

what do we call cells produced by mitosis?

daughter cells

how many cells does mitosis create?

mitosis produces 2 cells

( 1 cell divides into 2)

why is mitosis needed to create new cells?

1. to grow (e.g. bones, muscle)

2. to replace worn out cells (e.g. blood cells, skin)

3. to repair damaged tissue (e.g. wounded skin)

describe the cell cycle:

1. interphase- dna is copied

2. mitosis- replicated chromosomes separate and move to opposite ends of the cell

3. cytokenesis- splits into two daughter cells

what happens to the number of cells during mitosis?

• number of chromosomes stays the same

• the cell replicates its DNA so each chromosome now consists of two new identical sister chromatids

• this doubled the amount of DNA, but the number of chromosomes stays the same (they are just duplicated)

what is a stem cell

an undifferentiated cell

what is meristem tissue?

located in tips and roots of plants, similar to embryonic stem cells but for plants.

define diffusion

diffusion is the net movement of particles from an area of high concentration to an area of low concentration. the particles move down their concentration gradient. it is passive- does not require energy.

what are some examples of diffusion occuring in animals

• small intestine: glucose moves from the small intestine into the blood

• alveoli in lungs: O2 diffuses into the blood from the alveoli / CO2 moves from the blood into the alveoli, where it is breathed out.

what is an example of diffusion occuring in plants?

in plants, gas exchange occurs, with oxygen leaving the plant, moving from a high concentration to a low concentration of oxygen.