Biology Flashcards
Homeostasis Def.
Maintaining A Constant Internal Environment
Control System Pathway
Receptors —> Coordination Centre —> Effectors
Pituitary Gland Def.
Stimulates Production Of Hormones
Thyroid Gland Def.
Produces Hormones, Regulates Metabolic Rate
Adrenal Glands Def.
Produces Hormones To Regulate Metabolism & Blood Pressure, Create “Fight Or Flight” Body Response
Pancreas Def.
Produces Hormones Insulin & Glucagon
Ovaries Def.
Produce Hormone Oestrogen & Regulate Menstrual Cycle
Testes Def.
Produces Hormone Testosterone & Stimulates Sperm Production
Human Nerves System Pathway
Stimulus —> Receptor —> Sensory Neurones —> Coordinator —> Motor Neurones —> Effector —> Response
Examples Of Reflex Actions
Blinking, Breathing, Coughing Sneezing, Etc
Synapse Def.
Junctions Between Neurones
Ruler Drop (Reaction Rate) Practical Steps
- One Person Holds Ruler (From 0cm) Above The Second Persons Hand
- Person Drops Ruler & Starts Timer
- Second Person Detects This From Peripheral Vision
- Second Person Catches Ruler
- Repeat & Calculate Mean Result
Pancreatic Hormones And Use
Insulin (Decreases Blood Glucose Levels Back To Normal), Glucagon (Increases Glucose Levels Back To Normal)
Type 1 Diabetes & Def.
Pancreas Fails To Produce Insulin. Treated With Insulin Injections
Type 2 Diabetes Def. & Treatment
Body Cells No Longer Respond To Insulin, Treated With Healthy Diet & Exercise
FSH Hormone Def.
(Produces In Ovaries) Matures Egg
LH Hormone Def.
(Produced In Ovaries) Stimulates Release Of Egg
Oestrogen & Progesterone Def.
(Produced In Ovaries) Maintains Uterus Lining & Prepares For Pregnancy
Testosterone Def.
(Produced In Testes) Stimulates Production If Sperm
Examples Of Hormonal Contraception
Oral (BC. Pill), Progesterone Injections / Patch
Examples Of Non-Hormonal Contraception
Barrier Method (Condoms), Implant (Coil), Sterilisation (Permanent - Vasectomy)
IVA/F Steps
- Mother Is Given FSH & LH Injections
- Eggs (From Mother) Are Fertilised By Sperm From Father
- Premature Embryos Inserted Into Mother’s Uterus
Ethical Issues With IVA/F
High Chance Of Embryo Being Destroyed In Uterus Or Fertilisation Process, Against “God’s Plan”
Adrenaline Def.
Produced In Adrenal Gland, Creates “Fight Or Flight” Response In Body
Thyroxine Def.
Produced In Thyroid Gland, Stimulates Metabolism & Maintains Body Temp
Sexual Reproduction (In Humans)
Egg (23 C.) + Sperm (23 C.) —> Zygote (Embryo - 46C. / 23 Pairs)
Asexual Reproduction (In Plants)
(Mitosis) Prophase —> Metaphase —> Anaphase —> Telophase —> Cytokinesis
Mitosis Def.
One Division, Two Identical Daughter Cells
Meiosis Def.
Two Divisions, Four Identical Daughter Cells, Only In Gametes
Nucleus Def.
Contains Chromosomes
DNA Def.
Contains Genetic Instructions For Development & Function Of An Organism
Genetic Inheritance Def.
1 Gamete Cell = 46 Chromosomes / 23 Pairs
In Each Pair There Is One Chromosome Inherited From Mother & One From Father
Genome Def.
Entire Genetic Material Of An Organism
Genetic Mutation Def.
DNA Changes - Alters Instructions
Gene Def.
Sections Of DNA In A Chromosome
Allele Def.
Variations Of Given Gene
Homozygous Def.
Two Identical Alleles
Heterozygous Def.
Two Different Alleles
Genotype Def.
Genetic Make Up Of An Individual Orgainism
Phenotype Def.
Observable Characteristics Of An Individual, E.g: Eye Colour / Petal Colour
Dominant Def.
The Allele That Is Always Expressed In A Phenotype
Recessive Def.
An Allele That Shows Up In The Phenotype Only When It Is Heterozygous
Polydactyl Disorder Def.
Having Too Many Fingers / Toes, Inherited By Parent With Dominant Gene
Cystic Fibrosis Disorder Def.
Breathing Condition, Causes Mucus Build Up In Lungs, Must Have Two Parents With / Carrying Condition As The Allele Is Recessive
Embryo Screening Def.
Observing Embryo In Uterus To Check For Any Mutations Or Medical Disorders
(Genetic) Variation Def.
The Phenotype Of An Organism Is Determined By A Combination Of It’s Genotype & How It Interacts With It’s Environment
How Do Mutations Happen? (Origin)
All Genetic Variations In A Population Originate From Past Mutations (Changes In DNA) - Benefits Survival Chances Of An Organism
