Science AT4 Flashcards
Memorise
What are alpha particles?
- Extremely low in penetrating power and can take only a sheet of paper to stop it
- Emitted from some radionuclides (an unstable form of a chemical element that releases radiation as it breaks down and becomes more stable) during a form of radioactive decay called alpha-decay
What are Beta Particles?
- Has high energy and speed
- Negatively charged beta particles are identical to electrons
- Beta particles are capable of skin burns
- It takes a layer of clothing or a few mm of a substance to prevent this radiation
- Emitted from nucleus during radioactive decay
What is Gamma particles?
- Has extremely high penetrating power
- It will pass completely through the human body (damaging DNA and tissues)
- They are electromagnetic waves, not radiation
- Takes layers of dense substances to stop such as lead
- Emitted by an unstable nucleus of an atom during radioactive decay
What is half life
Half-life is the time it takes for half of a radioactive substance to decay or transform into another element.
Equation for Half life is N(t) = N0(1/2) to the power of time divided by time/2
An example of this would be Imagine you have a sample of 100 grams of a radioactive substance with a half-life of 4 years. How much of the substance will remain after 12 years?
Given:
Initial amount (N0) = 100 grams
Half-life (t1/2) = 4 years
Time elapsed (t) = 12 years
Answer would be 12.5 as t divided by 4 = 3, then 1/2 x 3 = 1/8. Then you would do 1/8 x 100 = half-life.
What are ions?
Ions are charged particles that form when atoms gain or lose electrons
What is a cation ion, and an anion. What is the difference?
- Cation (Positive): When atoms lose one or more electrons, it becomes a cation
- Anion (Negative): When atoms gain one or more electrons, it becomes an anion
What is an ionic bond?
Ionic bonds are what helps to stabilize through completing its valence shell
What do common Ions end with?
Often have names ending in “-ide” or suffixes like “-ate” or “-ite”
What is a Valence shell?
In chemistry, the valence shell is the outermost shell of an atom, housing the valence electrons. These electrons are the ones involved in chemical reactions and bonding with other atoms. The number of valence electrons determines an atom’s reactivity and bonding behavior. Essentially, the valence shell plays a crucial role in how atoms interact to form molecules and compounds.
What is an atom
Basic building blocks of matter. They are the smallest units of an element and retain the properties of that element
What is a proton
- Charge: Positive (+1)
- Location: In the nucleus (the Centre of the atom)
- Mass: approximately 1 atomic mass unit (AMU)
What is a neutron
- Charge: Neutral (no charge)
- Location: in the nucleus (the center of the atom )
- Mass: Approximately 1 AMU
What is an electron
- Charge: Negative (-1)
- Location: In the electron shells or energy levels surrounding the nucleus
- Mass: Approximately 1/1836 amu (much smaller than protons and neutrons)
How do you find the atomic number and the mass number?
- Atomic Number: The number of protons in the nucleus of an atom
- The number of electrons are equal to the number of protons
- The number Neutrons = Mass Number - Atomic Number
- Mass Number: The total number of protons and neutrons in the nucleus
What is the oestrogen?
Estrogen is a group of hormones that play a crucial role in the development and regulation of the female reproductive system and secondary sexual characteristics.
- Oestrogen is essential for the menstrual cycle (regulates ovulation and prepares uterus for pregnancy)
- Contributes to the development of breasts and wider hips
- Helps to maintain bone density and strength
- Affects mood, skin health and cardiovascular health
- Works alongside progesterone
- Production
- Ovaries
What is the Progesterone
- Progesterone is a hormone that plays a key role in the menstrual cycle, pregnancy, and embryogenesis in humans.
- Embryogenesis is when eggs are turned into embryos
- Function
- Helps to thicken and maintain the uterine lining
- Helps contribute to breast development
- Prevents further ovulation
- Overall maintains a healthy pregnancy
- Works alongside oestrogen
- Production
- Ovaries after ovulation
- Adrenal glands
- During pregnancy, the placenta
What is the Thyroxin?
Thyroxine is a hormone produced by the thyroid gland. It plays a critical role in regulating metabolism and growth in the body
- Controlling the speed of metabolism, influences how quickly the body uses energy, effects weight and energy levels.
- Growth and development
- Regulate heart rate and blood pressure
- Regulation in body temperature, influencing how the body heats.
Thyroid gland
What and where is the thyroid gland?
The thyroid gland is a butterfly-shaped organ located in the lower front of your neck, just below the Adam’s apple. It plays a crucial role in regulating your body’s metabolism by producing hormones that control how your body uses energy. These hormones influence nearly every cell in your body, affecting your heart rate, body temperature, and even your mood.
What is Insulin and Glucagon?
- Insulin: Hormone produced by the pancreas that regulates blood glucose levels
- Glucagon: Hormone produced by the pancreas that has the opposite effect of insulin but still regulates blood glucose levels
- Insulin helps to regulate blood glucose levels by reducing
- Glucagon helps to regulate blood glucose levels by increasing
Pancreas
What is adrenaline?
Hormone and neurotransmitter produced by the adrenal glands
Body’s fight or flight response, preparing the body to react during stressful situations
Adrenal Glands
What are the Adrenal Glands?
Adrenal glands are small, triangular-shaped glands located on top of each kidney. They’re vital for producing hormones that help regulate your metabolism, immune system, blood pressure, and stress response. The adrenal glands consist of two main parts: the cortex and the medulla.
What is the Cortisol
Hormone produced by the adrenal glands, specifically in the adrenal cortex. Relates to “stress hormone”
- Body’s response to stress and helps regulate various bodily functions
- Helps the body to manage and respond to challenging situations
- Increases blood glucose levels
- Helps to reduce inflammation
- Maintains blood pressure
Adrenal cortex (Outer layer of adrenal glands)
What is the growth hormone
Hormone produced by the anterior pituitary gland
- Growth
- Development
- Metabolism
- Mobilise fat stores and promotes the use of fat for energy
- Influences carbohydrate metabolism by promoting insulin resistance (maintains blood glucose levels)
What is the peripheral nervous system?
The PNS consists of all the nerves outside the CNS that connect the brain and spinal cord to the rest of the body
- Carry information from sensory receptors (skin, etc) to the CNS
- Transmit commands from the CNS to muscles and glands
