What does a nucleus do? - correct answer ✔It contains genetic material and
controls the activities of the cell
What does cytoplasm do? - correct answer ✔It's a gel-like substance where
most of the chemical reactions happen. It contains enzymes that control these
chemical reactions
What does a cell membrane do? - correct answer ✔It holds the cell together
and controls what goes in and out
What do mitochondria do? - correct answer ✔These are where most of the
reactions for aerobic respiration occur. Respiration transfers energy that the
cell needs to work
What do ribosomes do? - correct answer ✔This is where protein synthesis
takes place - where proteins are made in the cell
What do cell walls do? - correct answer ✔They are made of cellulose and
they support and strengthen the cell
What does a vacuole do? - correct answer ✔It contains cell sap and helps
maintain the shape of the cell
What do chloroplasts do? - correct answer ✔This is where photosynthesis
occurs, which makes food for the plant. They contain chlorophyll - a green
pigment - which absorbs light needed for photosynthesis
,What do bacterial cells contain? - correct answer ✔Cytoplasm, cell
membrane, cell wall, flagella, ribosomes, mitochondria, slime capsule,
plasmids (small rings of DNA) and a single circular strand of DNA that floats
freely in the cytoplasm
What do bacterial cells NOT contain? - correct answer ✔A nucleus
What is the equation for magnification? - correct answer ✔Image size
divided by actual size
What is differentiation? - correct answer ✔The process by which a cell
changes to become specialised for its job
What are undifferentiated cells called? - correct answer ✔Stem cells
What are sperm cells specialised for and how are they specialised? - correct
answer ✔Reproduction - they transport the male DNA to the female DNA
-It has a flagella and a streamlined head to help it swim towards the egg
-There are lots of mitochondria in the cell to provide the energy needed
-It carries enzymes in its head to help digest through the egg cell membranes
What are nerve cells specialised for and how are they specialised? - correct
answer ✔Rapid signalling - they carry electrical signals from one part of the
body to another
-They are long to cover more distance
-They have branched connections at their ends to connect to other nerve cells
and form a network throughout the body
,What are muscle cells specialised for and how are they specialised? - correct
answer ✔Contraction - they need to contract quickly
-They are long so they have space to contract
-They contain lots of mitochondria to generate the energy needed for
contraction
What are root hair cells specialised for and how are they specialised? - correct
answer ✔Absorbing water and minerals
-They are cells on the surface of plant roots which grow into long hairs that
stick out into the soil
-They have a large surface area for absorbing water and mineral ions from the
soil
What are chromosomes? - correct answer ✔Coiled up lengths of DNA
molecules that are found in the nuclei
What do multicellular organisms use mitosis for? - correct answer ✔To grow
or replace cells that have been damaged
What are stem cells? - correct answer ✔They are undifferentiated cells that
divide to produce lots more undifferentiated cells. They then differentiate into
different types of cell
Where are stem cells found? - correct answer ✔In early human embryos or
the bone marrow of adults
What do embryonic stem cells do? - correct answer ✔1) Used to replace
faulty cells in sick people - insulin-producing cells for diabetes and nerve cells
for paralysed spinal injuries
2) Used to replace faulty blood cells
, What is diffusion? - correct answer ✔Diffusion is the movement of particles
from an area of high concentration to an area of low concentration
Name the substances that can diffuse through cell membranes - correct
answer ✔Glucose, water, oxygen and amino acids
Name two substances that can't diffuse through cell membranes - correct
answer ✔Protein and starch
What is osmosis? - correct answer ✔Osmosis is the passive movement of
water molecules through a partially permeable cell membrane from an area of
high water concentration to an area of low water concentration
What are the two main differences between active transport and diffusion? -
correct answer ✔Active transport uses energy whereas diffusion doesn't.
Active transport goes against the concentration gradient whereas diffusion
goes along it
Adaptations of Exchange Surfaces - correct answer ✔1) Large surface area -
lots of substances can diffuse at once
2) Lots of blood vessels - to get stuff into and out of the blood quickly
3) Thin membrane - short distance for substances to diffuse
4) Often ventilated - air moves in & out
Give two ways that the villi in the small intestine are adapted for absorbing
digested food - correct answer ✔1) A single layer of surface cells
2) A very good blood supply to assist quick absorption