Bio paper 1

What is a triglyceride

Glycerol and three fatty acids joined by ester bonds

What is starch made from

alpha glucose

Amylose (1,4) (coiled) and Amylopectin (1,4) (1,6) (Branched)

What is glycogen

A polysaccharide (1,4) (1,6)

What type of melting point do saturated fats have

a high melting point

Why is the dipole nature of water so important

because it allows water molecules to form hydrogen bonds with each other

Dna replication

Semi-conservative, Uses DNA bases, Uses DNA polymerase, Creates double stranded DNA

What enzymes are used for cutting DNA into fragments in gel electropheresis

Restriction Enzymes

What are Nitrate ions used for

Required to make amino acids and DNA

What are calcium ions used for

Calcium pectate for the middle lamellae

What are phosphate ions used for

ADP, ATP, DNA and RNA

What are magnesium ions used for

Needed for chlorophyll

Structure of Cellulose

Polysaccharide of B glucose Microfibrils held together by hydrogen bonds. Arranged in a criss cross pattern (1,4 bonds)

Tissue

Group of many cells that work together for a common function

How can we ensure a practical is valid

Control: both biotic and abiotic

Repeats

Same method used

what are lipids made of

Hydrophilic head containing a glycerol and a phosphate group

Hydrophobic fatty tails

Draw a peptide bond

What size are ribosomes in different types of cells

Eukaryotes: 80s Prokaryotes: 70s

What does the RER do

Fold polypeptide chains into secondary/tertiary structures

What cells are centrioles found in

Only animal cells

What are the general stages of the cell cycle

• Interphase

  -(G1, G2, S)

• Mitosis

• Cytokenesis

What happens in cytokenesis

The cytoplasm fully divides creating new cells

What happens in G1 phase

The organelles in the cell double and the cell grows in size

What occurs in the S phase

DNA replication occurs

What occurs in G2

Further growth and DNA checking for mutations

What occurs in Prophase

• Chromosomes condense and become visible

• Centrioles appear

• Nuclear envelope begins to disintegrate

What occurs in metaphase

• Chromosomes line up on the equator

• Spindle fibres attach to the centromere on the chromatids

What occurs in anaphase

• Spindle fibres begin to separate

• Splits chromosomes

• (Requires ATP)

What occurs in Telophase

• Chromosomes are now at each pole of the cell and begin to become longer and thinner again

• Nuclear envelopes begin to reform

• Spindle fibres break down

What stain would you use in the root tip practical

Acetic orcein

Rough steps of the root tip practical

• Place roots in warm Hydrochloric acid

• Take out and rinse with water

• Stain root tips with acetic orcein

• Heat in water bath

What is crossing over and when does it occur

Swapping sections of DNA

Prophase 1

Adaptions of sperm

• Many Mitochondria

• Shape

• Acrosome

• Flagellum

• Haploid nucleus

Why does the sperm release enzymes

• comes into contact with zona pellucida

• causing acrosome to rupture

What fuses to create a triploid endosperm

one male gamete and two polar bodies

What is the formation of sperm order

• Spermatagonia

• Primary spermatocytes

• secondary spermatocytes

• spermatids

• Spermatazoa

Effects of antibodies

1. Agglutination (Microbes clump together making phagocytosis easier)

2. Lysis (Bursting of bacterial cells)

3. Opsonation (Coat bacterial cells essentially marking them form phagocytosis)

4. Precipitation ( Soluble toxins made Insoluble)

What is the final electron acceptor in the light dependent reaction

NADP

Endemic

Native to a specific location and not found anywhere else

How are seeds selected for the seed bank

X-rayed for viability and a range of seeds selected for genetic variation

Stud books

Help in breeding programmes increasing genetic diversity

Inbreeding Vs Intebreeding

Interbreeding: Breeding 2 different species Inbreeding: Two individuals of the same species with similar genetics

Why are some animals better protected in protected reserves

• Less stressful for the animal

• May require large ares

• Less susceptible to disease

• Wider gene pool

• Natural diet available

In situ conservation

• Education programmes

• Nature reserves

How does gel electrophoresis work

• Multiple copies of DNA made using PCR

• Restriction enzymes used to cut into fragments

• Loaded into Into Agarose gel

• Current applied

• Use of fluorescent tag

3 Domains

Archae, Bacteria, Eukarya

Why might two species not breed

• DIfferent breeding times

• Do not recognise courtship displays

• Physically incompatible

Genetic diversity

Variety of alleles in a gene pool

How does natural selection occur

• Selection pressure

• Results in selection for an advantageous phenotype

• Advantageous alleles passed on through reproduction

• Change in genotypes over generations

Ecological niche

The role an organism plays in an ecosystem with regards to its interactions with other species and where it lives (trophic level as well)

How does a heart attack occur

• Blood clot in coronary artery

• causing the heart to be starved of oxygen

• meaning no aerobic respiration can occur

• this will cause the cells to die in the heart

Myogenic

• Stimulation generated from within the muscle

• This results in depolarisation

Why would regular exercise decrease risk of developing CVD

Regular exercise would decrease blood pressure

Order of heartbeat control

• SAN initiates wave of depolarisation in the right atrium

• Atria contracts

• Region of non conducting tissue confines depolarisation to the atrium

• Stimulates the AVN

• This passed a wave of depolarisation into the bundle of his with a delay

• Bundl of his splits in two called the purkyne fibres

• causes contraction from the bottom of the ventricle

Plasmodesmata

How are mammals adapted for gas exchange

• Large surface area through capillaries, alveoli

• Difference in concentration gradient through ventilation of lungs and mass circulation system

• Length of diffusion pathway: Thin capillary and alveoli walls

How does gas exchange occur in insects

• Spiracles- allow air in

• Air travels down the trachea which is lined with chitin

• Then air diffuses into tracheloes which are permeable

How are insects adapted for gas exchange

• Can remove water from tracheole ends by causing a lactic acid buildup

• Chitin rings keep the tracheole tubes strong

• Some insects can ventilate their air systems by mechanical ventilation

How does gas exchange occur in fish

• Mouth opens and operculum closes

• Mouth closes which causes operculum to open

• water rushes over the gills

How are fish adapted for rapid gas exchange

• High surface area, many lamella on many Gill filaments

• Countercurrent flow in the lamella

• Large capillary network

Xylem

• Cellulose

• lignified in spirals

• Pits in the side

• Pectin in the cell wall

Why does tissue fluid return into the capillaries

• More protein in plasma than tissue fluid

• As plasma proteins are too large to pass out of capillary

• Oncotic pressure greater than hydrostatic

Summarise the mass flow hypothesis

• Sugar loaded into sieve tubes via active transport

• Lowers water potential causing water to move in from xylem

• Hydrostatic pressure causes sugars to move

Evidence for mass flow hypothesis

• Sap is released when a stem is cut therefore there must be a high pressure in the phloem

• There is a higher sucrose conc. in the leaves than the roots

Phloem structure

• Consists of sieve tubes made of many cells joined together to to create a long tube

• Sieve plates

• Companion cells

Evidence against the mass-flow hypothesis

• Not all solutes move at the same speed

• There is bidirectional movement in the sieve tubes

Where does glycolysis take place

The cytoplasm

Where does the link reaction take place

Mitochondrial matrix

Where does the Krebs cycle occur

Mitochondrial matrix

Where does ETC take place

Inner membrane of the mitochondria

How can anaerobic respiration release energy

• ATP may already be present

• ATP can be produced from glycolysis which is rapid

• Some aerobic respiration will occur

• NAD recycled

• Lactate tolerance

What happens to lactate after anaerobic respiration

• Broken down in the liver

• into pyruvate

• Involving production of NADH

• which is then used for respiration

How is pyruvate formed

• Through the process of glycolysis

• Hexose molecule (glucose) phosphorylated

• Breakdown to glycerate 3 phosphate

• Production of ATP and NADH

How is pyruvate converted to Acetyl coA

• Link reaction

• Pyruvate converted to Acetate

• CoA added to make Acetyl CoA

What does the Krebs cycle do

• Completely oxidises Acetyl coA

• To release as much energy as possible

• To generate ATP directly

• Producing reduces coenzymes

• So ATP can be produced in the electron transport chain

What is the final electron acceptor in the electron transport chain

• Oxygen to produce water

Anaerobic respiration in plants

• fermentation of glucose to produce ethanol and co2

Carbon fixation

• CO2+RUBP= GP

• Catalysed by RUBISCO

What does a chloroplast not have

• A matrix

• Instead it has a stroma

what is the channel protein that is used to make ATP in oxidative phosphorylation

• ATP synthase

final electron acceptor in photosynthesis

• Reduced NADP

How does glycolysis operate in anaerobic conditions

• NADH used to convert pyruvate into lactate

• instead of being sent to the electron transport chain

Streak plate Vs spread plate

• Streak plate is when three streaks of culture, rotated by 90 degrees

• Spread plate is when culture is poured on plate and then spread around with a spreader

Benefits of broth over agar

• Broth can provide anoxic conditions but with oxygen closer to the surface

• You can get a much larger volume of bacteria

• Can’t get discrete colonies

Order of microorganism growth

1. Lag phase

2. Log phase

3. Stationary phase

4. Death phase

Lag phase

• Microorganisms adapting to their environment

• Reproduction increase slowly

Log phase

• Microorganisms grow at max rate

Stationary phase

• Death rate = reproduction rate

• This is due to buildup of waste products and lack of nutrients

Death phase

• Deaths exceed new reproduction rate

Cell count

• Use a haemocytometer

• Only counts viable cells

• slow and expensive

Turbidimetry

• Measure absorbance using a colorimeter

• Quick and can be conducted in the field

• counts dead cells

Dilution plating

• Works on the principle that every colony is grown from a single viable microorganism

• colonies counted and then multiplied by dilution rate to find original cell count

• DOesnt require expensive or complex equipment

• slow as incubation period needed

Gram negative bacteria

• Extra lipopolysaccharide layer

• Contain endotoxins

• ie Salmonella

Gram positive bacteria

• No lipopolysaccharide layer

• No endotoxins

• Staphylococcus which release exotoxins

Penicillin

Bacteriocidal

Tetracycline

Bacteriostatic

Puccinia graminis (stem rust fungus)

• Wind carries spores and infected fragments left in the ground

• Spores germinate in water on plants

• producing hyphae which grow into mycelium which surround plant tissue

• Which digest the plant

• Weakens the plant

• Steals water and nutrients

• reduced transpiration

Influenza

• Droplet infection

• Infects ciliated epithelial cells

plasmodum spp. (protozoa) (malaria)

• Transmitted through anopheles vector

• Parasite transmitted via mosquito

• Travels to liver, infects red blood cells

• reproduces asexually in red blood cells

• blood bursts every 2-3 days

• can be treated with antimalarial drugs ie quinine

Problems of controlling endemic diseases

• Disease is often widespread

• Difficult to remove all sources

• treatment can be expensive

• ie for malaria

• Preventing mosquito bites

• Controlling mosquito population