Unit 2 Flashcards
Name 3 plant organs
Roots
Stem
Leaves
What main substances are transported by plant organs?
Water
Minerals
Sugar
How are water and minerals taken from soil to plant leaves?
The roots absorb the water & minerals
The stems transport it
The leaves receive it
What 2 main reasons is water needed for in plants?
- PHOTOSYNTHESIS - Plants making food from sunlight. Happens in leaves.
- TRANSPORTING DISSOLVED MATERIALS - For example minerals.
How do plant roots absorb water?
Root Hair Cells
They have large surface area to be efficient.
How do plant stems transport water and minerals?
Xylem tubes are:
Hollow
Made of dead cells
Lignified (strengthened with lignin)
This allows xylem to withstand water pressure changes in transport.
Define transpiration.
The process of water moving through the plant and evaporating from the stomata on leaves.
How does transpiration work?
Water is lost from stomata (pores). They can be open or closed.
Guard Cells control the opening and closing of stomata.
What gases are absorbed from plant leaves by stomata?
Carbon Dioxide
How does wind speed affect transpiration?
Wind speed INCREASES transpiration because the water released by transpiration is blown away from the plant quicker.
How does humidity affect transpiration?
Humidity DECREASES transpiration because the water will evaporate slower in already wet conditions.
How does temperature affect transpiration?
Increased temperature increases transpiration because higher temperatures cause water to evaporate faster.
How does surface area affect transpiration?
Increased surface area increases transpiration because there are more stomata for water to leave from.
How is the rate of transpiration measured?
With a potomer.
Glucose is made in the leaves of a plant during __
Photosynthesis
How is sugar transported through a plant?
Phloem
What is phloem made from?
Living tissue
What is the function of the UPPER EPIDERMIS?
A layer of transport cells.
They allow light to pass through to the next layer.
Define fertilisation.
Fertilisation is the fusion of the nuclei of two haploid gametes to produce a diploid zygote which divides to form an embryo.
How can transpiration rate be measured?
Using a potometer.
State 4 facts about the heart.
- Has 4 chambers
- 4 valves to prevent backflow of blood
- 4 associated blood vessels
- Coronary arteries provide nutrients and oxygen
State the 3 types of blood vessels.
Vein
Artery
Capillary
State the structure and function of an artery.
Structure: Thick muscular wall, narrow central channel
Function: Carry blood at high pressure away from the heart
State the structure and function of a human vein.
Structure: Thin muscular wall, wider central channel, contain valves
Function: Carry blood at low pressure back into the heart
State the structure and function of a capillary.
Structure: Thin walls, large surface area, form networks at organs and tissues
Function: Allows exchange of materials between blood and cells
What is blood in mammals made of?
Red blood cells
White blood cells (phagocytes, lymphocytes)
Plasma
State 2 facts about white blood cells.
- Part of the immune system
- Destroy pathogens
State 3 facts about the structure of red blood cells.
- Biconcave shape
- No nucleus
- Contains haemoglobin
State 2 types of white blood cell and their functions.
Phagocytes: carry out phagocytosis by engulfing and digesting pathogens.
Lymphocytes: Produce antibodies specific to just one type of pathogen.
What 2 materials must be absorbed into the bloodstream and why?
Oxygen
Nutrients from food
They must be delivered to cells for respiration.
What materials must be removed from the bloodstream?
Waste materials such as carbon dioxide.
What 3 features do surfaces involved in the absorption of materials have in common and why?
Large surface area
Thin walls
Extensive blood supply
These features all increase the efficiency of absorption.
What are the 3 food groups?
- Carbohydrates (starch)
- Proteins
- Fats
What are the 3 food groups broken down into by enzymes?
- Glucose (Carbs)
- Amino acids (Proteins)
- Fatty acids and glycerol (Fat)
How are nutrients from food absorbed?
By the Villi (villus) in the small intestine.
In a villus, what does the network of capillaries do?
Absorbs glucose and amino acids.
In a villus, what is the lacteal responsible for?
Absorbing fatty acids and glycerol.
How is oxygen absorbed in humans?
Into the alveoli in the lungs.
How does an alveolus give oxygen and remove carbon dioxide?
- Oxygen is absorbed from the thin alveolar walls into the capillaries.
- Carbon dioxide is absorbed into the thin alveolar walls from the capillaries.
What is the process of cell division called?
Mitosis
Why is mitosis important?
It provides new cells for the growth and repair of damaged cells and maintains the diploid chromosome complement.
How many chromosomes are in a human cell?
46 (2 pairs of 23)
What are the main stages of mitosis?
- The chromosomes replicate and become visible. Each chromosome is two chromatids joined together.
- The nucleus breaks down.
- The chromatids line up along the equator of the cell. Spindle fibres attach to the middle of the chromatids.
- Spindle fibres pull the chromatids apart. The chromatids are pulled to opposite poles of the cell.
- Separated chromatids are now called chromosomes and nuclear membranes form around them.
- The cytoplasm splits. Two daughter cells are made.
How many chromatids does a chromosome contain?
2
Draw a diagram representing mitosis.
idk check notes
STEM CELLS in animals are ___ which can divide to make more stem cells.
UNSPECIALISED cells.
Stem cells are responsible for __
Growth and Repair.
Where can stem cells be extracted from?
Stem cells can be extraced from Embryo at a very early stage.
What is specialisation?
Specialisation is when a stem cell becomes a specific type of cell. It leads to the formation of a variety of cells, tissues and organs.
What are tissues?
A group of cells that carry out a similar function.
What are organs made of?
A collection of tissues.
What are systems?
A collection of organs.
Show the chain of cells to systems.
Cells > Tissues > Organs > Systems
What is the nervous system made up of?
Brain
Spinal Cord
Nerves
What is the Central Nervous System (CNS) made up of?
Brain
Spinal Cord
What are the main regions of the brain?
Cerebrum (top wrinkly part💀)
Medulla (weird stem…)
Cerebellum (lump thing beneath cerebrum)
What is the cerebrum responsible for?
Personality
Logic
Intelligence
Memories
What is the cerebellum responsible for?
Balance
Coordination
What is the medulla responsible for?
Breathing
Heart Rate
What is a neuron?
A nerve cell