DNA is a Double Helix Flashcards by Verity Russell

What is a DNA molecule?

Two strands coiled together in the shape of a double helix

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What are the two strands held together by?

Bases

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What are the 4 different bases?

Adenine (A)
Cytosine (C)
Guanine (G)
Thymine (T)

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What are bases in relation to each other?

Bases are paired

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What are the two types of complementary-base pairing?

A-T

C-G

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What is DNA a type of?

Nucleic acid

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CGP GCSE Biology (226 decks)

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Characteristics of Living Organisms

Organelles in typical animal cell

Organelles in typical plant cell

Cells are Specialised

Tissues are Organised into Organs

Organs Make Up Organ Systems

Some Organisms Are Pathogens

Enzymes Are Catalysts Produced by Living Things

Enzymes are Very Specific

Enzymes Like it Warm but Not Too Hot

You Can Measure a How Fast a Product Appears

... Or How Fast a Substrate Disappears

Enzymes Also Need the Right pH

Don’t be Put Off by the Fancy Word

Cell Membranes are Pretty Clever

Osmosis is a Special Case of Diffusion

Water Moves Into and Out of Cells by Osmosis

Plants Are Supported by Turgid Cells

You Can Investigate Diffusion in a Non-Living Syste,

Investigate Osmosis in Living System

Investigate Osmosis in Non-Living Systems

Active Transport is the Opposite of Diffusion

Three Main Factors Affect The Movement of Substances

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Responding to their Environment Helps Organisms Survive

Receptors Detect Stimuli and Effectors Produce a Response

The Central Nervous Systems (CNS) Coordinates Information

Reflexes Help Prevent Injury

The Reflex Arc Goes Through the CNS

Learn the Eye

In Clockwise order list all the labels of the Eye

The Iris Reflex - Adjusting for Bright Light

Focusing on Near and Distant Objects - Another Reflex

Long-sighted people

Short-sighted people

Hormones are Chemical Messengers Sent in the Blood

Key Hormones and Their Roles in the Body

Hormones and Nerves Do Similar Jobs, but There Are Differences

Homeostasis - it’s all about Balance

Water Is Lost from the Body in Various Ways

Body Temp is Kept at About 37 °C

Skin Plays an Important Role in Maintaining Body Temperature

Smaller Organisms Can Cool Down Quicker

Plants Need to Respond to Stimuli too

Auxins are Plant Growth Hormomes

Auxins Change the Direction of Root and Shoot Growth

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Carbohydrates are Made Up of Simple Sugars

Proteins are Made Up of Amino Acids

Lipids are Made Up of Fatty Acids and Glycerol

You Can Test for Glucose Using Benedict’s Reagent

Use the Iodine Test for Starch

You Need to Eat Different Foods to Get Different Nutrients

A Balanced Diet Supplies All Your Essential Nutrients

Energy Requirements Vary in Different People

Food Can be Burnt to See How Much Energy it Contains

First You Need a Dry Food, Water and a Flame

Calculate the Amount of Energy in Joules

Calculate the Amount of Energy in Joules per Gram

The Accuracy of the Experiment Can be Increased

Digestive Enzymes Break Down Big Molecules into Smaller Ones

Bile Neutralises the Stomach Acid and Emulsifies Fats

Your Alimentary Canal Runs Through Your Body

Food is Moved Through the Gut by Peristalsis

Villi in the Small Intestine Help with Absorption

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Photosynthesis Produces Glucose Using Sunlight

Leaves are Designed for Making Food by Photosynthesis

Leaves are Adapted for Efficient Photosynthesis

The Limiting Factor Depends on the Conditions

Not Enough LIGHT Slows Down the Rate of Photosynthesis

Too Little CARBON DIOXIDE Also Slows it Down

The TEMPERATURE Has to be Just Right

You Need to Know How to Test a Leaf for Starch

Chlorophyll - Starch Test

CO2 - Starch Test

The Starch Test Shows Whether Photosynthesis is Taking Place

Oxygen Production Shows the Rate of Photosynthesis

Plants Need Three Main Mineral Ions For Growth

Nitrates

Phosphates

Potassium

Magnesium is Also Needed in Small Amounts

Multicellular Organisms Need Transport Systems

Plants Have Two Main Transport Systems

Root Hairs Take In Water

Transpiration is the Loss of Water from the Plant

Transpiration Rate is Affected by Four Main Things

A Potometer can be Used to Estimate Transpiration Rate

You Can See How Environmental Conditions Affect Transpiration Rates

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Respiration is NOT ‘Breathing In and Out’

Aerobic Respiration Needs Plenty of Oxygen

Anaerobic Respiration Doesn’t Use Oxygen At All

Anaerobic Respiration in Plants is Slightly Different

Carbon a Dioxide Production can be Detected using an Indicator

The Heat Produced by Respiration can be Measured

Plants Exchange Gases By Diffusion

The Next Exchange of Gases Depends on Light Intensity

Leaves are Adapted for Efficient Gas Exchange

Hydrogen-carbonate Indicator Shows Changes in CO2 Conc

...So You Can Use it to Show Differences in Net Gas Exchange un Plants

And The Results are in...

The Lungs Are in the Thorax

Breathing In...

...and Breathing Out

You Can Investigate the Effect of Exercsie no Breathing Rate

Alveoli Carry Out Gas Exchange in the Body

Alveoli are Specialised for Gas Exchange

Smoking Tobacco Can Cause Quite a Few Problems

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Blood has Four Main Components

Plasma is the Liquid Bit of Blood

Platelets are Small Fragments of Cells that Help Blood Clot

Red Blood Cells Have the Job of Carrying Oxygen

Your Immune System Deals with Pathogens

Phagocytes Ingest Pathogens

Lymphocytes Produce Antibodies

Vaccination - Protects from Future Infections

Blood Vessels are Designed for Their Function

Arteries Carry Blood Under Pressure

Capillaries are a Really Small

Veins Take Blood Back to the Heart

Parts of the Heart

Labels of Heart in Clockwise Order

Exercise Increases Heart Rate

The Hormonal System Also Helps to Control Heart Rate

Labels of Circulation System in Clockwise Order

You Need to Know the Structure of the Circulation System

The Kidneys are Excretion Organs

Ultrafiltration

Reabsorption

Release of wastes

The Kidneys Also Adjust the Body’s Water Content

ADH Helps to Control Water Content

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Genes are Chemical Instructions

DNA is a Double Helix

Asexual Reproduction Involves Mitosis

Mitosis Produces Genetically Identical Cells

Mitosis Also Makes New Cells for Growth and Repair

Sexual Reproduction Produces Genetically Different Cells

Gametes are Produced by Meiosis

The Stamen is the Male Reproductive Part - Flower

The Carpel is the Female Reproductive Part - Flower

Some Plants are Adapted for Insect Pollination

Pollination

Other Plants are Adapted for Wind Pollination

Fertilisation is the Fusion of Gametes

Germination is when Seeds Start to Grow

Germinating Seeds get Energy from Food Stores

Plants Can Reproduce Asexuality Using Natural Methods

... or We Can Clone Them Using Artificial Methods

The Male Reproductive System Makes Sperm

The Female Reproductive System Makes Ova (Eggs)

Hormones Promote Sexual Characteristics at Puberty

The Menstrual Cycle has Four Stages

Oestrogen and Progesterone Control the Menstrual Cycle

The Embryo Develops During Pregnancy

Alleles are Different Versions of the Same Gene

Genetic Diagrams show the Possible Alleles in the a Offspring

There’s Another Way to Draw Genetic Diagrams

You Can Draw Genetic Diagrams for Codominant Inheritance too

You Need to Understand Family Pedigrees

Your Chromosomes Control Whether You’re Male or Female

There’s an Equal Chance of Having a Boy or a Girl...

Genetic Variation is Caused by Genes

Most Variation in Animals is Due to Genes AND Environment

Environmental Variation in Plants is Much Greater

Make Sure You Know the Theory of Evolution

Natural Selection Means the ‘Survival of the Fittest’

The Best Genes for a Particular Environment Tend to Survive

Mutations are Changes to the Genetic Code

Bacteria can Evolve and Become Antibiotic-Resistant

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You Need to Learn Some Definitions to get you started

You Can Estimate Population Sizes in Different Areas Using a Quadrat

Two Important Points About This Kind of Counting Method

You Can Use Quadrats to Investigate the Distribution of Organisms too

Food Chains Show What’s Eaten by What in an Ecosystem

You Need to Understand Pyramids of Numbers

You Have to Understand Pyramids of Biomass too

Pyramids of Energy Transfer Are Always Pyramid-Shaped

Energy is Transferred Along a Food Chain

Food Webs Show How Food Chains are Linked

The Water Cycle Means Water is Endlessly Recycled

The Carbon Cycle Shows How Carbon is Recycled

Nitrogen is Also Recycled in the Nitrogen Cycle

Carbon Monoxide is Poisonous

Acid Rain is Caused by Sulfur Dioxide

Acid Rain Kills Fish and Trees

Greenhouse Gases Trap Heat from the Sun

Human Activity Produces Lots of Greenhouse Gases

Fertilisers can Leach into Water and Cause Eutrophication

Deforestation Affects the Soil, Water Cycle and Carbon Cycle

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You Can Artificially Create the Ideal Conditions for Photosynthesis

Fertilisers Are Used to Ensure the Crops Have Enough Nutrients

Pest Control Stops Pests Eating Crops

Bacteria Ferment Milk to Produce Yoghurt

Microorganisms are Grown in Fermenters

We Use Yeast for Brewing Beer

The Respiration Rate of Yeast Depends on Its Conditions

Selective Breeding is Mating the Best Organisms to Get Good Offspring

Selective Breeding is Very Useful

Fish Can be Farmed In Cages In The Sea

Fish Can Be Farmed In Tanks Too

Enzymes Can Be Used To Cut Up DNA or Join DNA Pieces Together

Vectors Can Be Used to Insert DNA Into Other Organisms

Genetically Modified Plants Can Improve Food Production

Micro propagation is Used to Clone Plants

Cloning an Adult Mammal is Done by Transplanting a Cell Nucleus

There Are Advantages and Disadvantages to Cloning

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DNA is a Double Helix Flashcards

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