B1 Cell Biology Flashcards
Where are embryonic stem cells found?
Embryo
Where are adult stem cells found?
In the body after birth. Bone marrow.
What is the disadvantage of adult stem cells?
They can only differentiate into most types of cells.
What are the three main organs of a plant?
Leaf, stem, roots
What is the function of the leaf?
Absorbs sunlight for photosynthesis
What is the function of the stem?
Transports nutrients around the plant
What is the function of the roots?
Absorbs water and mineral ions from the ground
What are the first type of cells formed in animals?
Stem cells
What are the first type of cells formed in plants?
Meristems
Where are meristems found?
Root tips
Can stem cells change cell type?
No, not once decided
Can meristem cells change type?
Yes, they can redifferentiate as required.
What is differentiation?
The process where cells become specialised at different points during development, giving them special features.
What is the equation for magnification?
Magnification = image size / actual size
Order the following: organ, cell, organelle, organ system, tissue
Organelle, cell, tissue, organ, organ system
What is the function of muscle tissue?
Contracts to allow movement
What is the function of glandular tissue?
Produces hormones/enzymes
What is the function of epithelial tissue?
Lines the surface of the organs for protection
What is transpiration?
The movement of water from the roots to the xylem - loss of water via evaporation
What is the function of a xylem cell?
To transport WATER AND MINERALS up the stem from the roots to shoots and leaves. This is a one-way transfer only.
What substance strengthens the xylem?
Lignin
What is the function of a phloem cell?
To transport SUGARS produced in the leaves up and down the stem to growing and storage tissues.
What is the movement of sugars through the phloem known as?
Translocation
What is the movement of water and mineral ions from the roots to the xylem known as?
Transpiration
What is the word equation for photosynthesis?
Carbon dioxide + water -> oxygen + glucose
What is the balanced symbol equation for photosynthesis?
6CO2 + 6H2O -> 6O2 + C6H12O6
What is the function of the guard cell?
Open and close the stomata to prevent water loss.
What is the function of the stomata?
Allows gas diffusion
What is the function of the air space?
Space for gases to diffuse
What is the function of the xylem?
Transports water and minerals
What is the function of the lower epidermis?
Forms a protective layer
What is the function of the phloem?
Transports food substances (sugars)
What is the function of veins on leaves?
Acts as a continuation of the stem
How does light intensity affect transpiration?
In bright light, transpiration increases
How does humidity affect transpiration?
Transpiration is slower in humid conditions
How does windy weather affect transpiration?
Faster in windy conditions
How does temperature affect transpiration?
Higher temperatures = faster rate of transpiration
What is a prokaryotic cell?
A cell without a nucleus
Where is DNA stored?
In the nucleus
What is the function of the cell membrane?
Controls movement of substances
What is the function of ribosomes?
Protein synthesis
What is the function of the cytoplasm?
Where chemical reactions take place
What is the function of the mitochondria?
Respiration
What is the function of the cell wall?
Strengthens the cell
What is the cell wall made of?
Cellulose
Where is DNA stored?
In the nucleus
What is the function of the vacuole?
Keeps the cell rigid
What does the vacuole contain?
Cell sap
What is a eukaryotic cell?
A cell with a nucleus
What are the features of the average bacterial cell?
Slime capsule, ribosomes, plasmids, flagella, cell membrane, genetic material, cytoplasm, cell wall
What did eukaryotic cells evolve from?
Prokaryotic cells
How would you cultivate bacteria in a school laboratory?
In a nutrient broth solution as colonies on an agar plate
What are amino acids?
Protein molecules that make up enzymes
Where are stem cells found in plants?
Meristem
What are the 4 components of blood?
Platelets, plasma, red blood cells, white blood cells
What is the function of platelets?
To clot wounds
What is the function of plasma?
To carry substances (liquid)
What is the function of white blood cells?
To fight off infection
What is the function of red blood cells?
To carry oxygen around the body
What do red blood cells contain to help them carry oxygen?
Haemoglobin
How are red blood cells adapted to carry oxygen around the body?
No nucleus (more space), contain haemoglobin, disk-shaped (small + flexible biconcave shape), large surface area
What is binary fission?
Dividing in order to increase the number of cells
What is diffusion?
The net movement of particles from a region of high concentration to a region of low concentration
How will a higher concentration gradient affect the rate of diffusion?
Higher concentration gradient = faster rate of reaction
You could increase the rate of diffusion by:
Increasing concentration gradient, increasing temperature, increasing surface area or decreasing distance for diffusion
Give 2 examples of diffusion:
Any 2 from:
ALVEOLI - gas exchange (oxygen and carbon dioxide)
VILLI - absorbing nutrients - microvilli to increase surface area and speed of diffusion
BACTERIA - absorbing oxygen
What is osmosis?
The net movement of water molecules from an area of high concentration to an area of low concentration across a partially permeable membrane
What is a partially permeable membrane?
A membrane with tiny holes
What is it called when a cell swells and bursts due to excess water?
To lyse
What happens if an animal cell loses water due to osmosis?
The cell shrinks and loses mass
What happens if an animal gains water due to osmosis?
The cell lyses (swells and bursts)
Name 2 examples of osmosis:
LARGE INTESTINE - absorbs water
STOMATA - water vapour leaving the stomata
ROOT HAIR CELLS - absorbing water
KIDNEYS
What is active transport?
The net movement of particles from a region of low concentration to a region of high concentration
What is required for active transport to take place?
Energy and a membrane for carrier proteins
What is ATP?
Energy
Give 2 examples of active transport:
ROOT HAIR CELLS - absorbing mineral ions from the soil
DIGESTION - small intestine (villi/microvilli) - GLUCOSE
Which type of particle transfer (diffusion/osmosis/active transport) works against the concentration gradient?
Active transport
How does surface area: volume ratio effect object size?
The larger an objects size, the lower the surface area: volume ratio
How do you calculate surface area: volume ratio?
SA = area of 1 side * number of sides. Leave in the form SA/V:1
How does the concentration gradient effect the rate of diffusion?
Higher concentration gradient = faster rate of diffusion
What is the equation for photosynthesis?
Carbon dioxide + Water –> Glucose + Oxygen
What type of reaction is photosynthesis?
Endothermic - it takes in heat from the sun
What is an exothermic reaction?
A reaction which releases heat/energy
What is an endothermic reaction?
A reaction which takes in heat/energy
What are the 3 uses for glucose when produced during photosynthesis?
- Respiration (energy release)
- Cellulose (cell walls)
- Starch (storage - insoluble)
Why is starch good for storage?
It is insoluble - it does not affect water concentration inside the cells
What are the 3 factors increasing the rate of photosynthesis?
- Higher temperature
- Higher carbon dioxide levels
- Higher light intensity
What are the 4 factors decreasing the rate of photosynthesis?
- Lower carbon dioxide levels
- Lower water concentration
- Lower temperatures
- Lower light intensity
How does the concentration of salt affect the weight of a potato chip? (Osmosis RPA)
Greater concentration of salt = more weight loss
How does the concentration of salt affect the weight of a potato chip? (Osmosis RPA)
Greater concentration of salt = more weight loss (water is absorbed by the salt)
How does light intensity affect the rate of photosynthesis? (Photosynthesis RPA)
Greater light intensity = faster rate of photosynthesis
What is the equation for respiration?
Oxygen + Glucose –> Carbon Dioxide + Water
How do you calculate percentage change?
% change = ((end weight - start weight) / (start weight)) * 100