Cells Flashcards
What is a cell?
The structural and functional unit of living organisms
What does an animal cell contain?
Nucleus Cell membrane Ribosomes Cytoplasm Mitochondria
What a plant cell contain?
Cell wall Cell membrane Nucleus Chloroplasts Vacuole Ribosomes Mitochondria Cytoplasm
What is a nucleus?
Controls all activities of the cell and contains the DNA
What is a ribosome?
Makes proteins for the cell?
What is cytoplasm?
Chemical reactions needed for life occur in the liquid gel
What is a cell membrane?
It controls the movement of substances in and out of the cell
What is mitochondria?
Helps in respiration releasing energy for the cell
What is a cell wall?
A firm non- living box around the cell to provide strength and structure
What is the vacuole?
A large space containing cell sap to keep the cell rigid
What is a chloroplast?
It contains chlorophyll which helps with photosynthesis
What does a bacterial cell contain?
Free floating DNA Cell membrane Cell wall Ribosomes Plasmids Cytoplasm Flagellum
What is a plasmid?
A small strand of DNA found in a bacterial cell
Why does it have a flagellum?
To help rotate the cell so it can move
What is a eukaryotic cell?
A cell with a nucleus and membrane bound organelles
What is a prokaryotic cell?
A cell with no nucleus and free floating DNA
How do u find the order of magnitude?
Bigger number/ smaller number
Name advantages and disadvantages of the light microscope
Uses beams of light- A
Is cheap-A
Needs light source-D
2D image-D
Name advantages and disadvantages of the electron microscope
Better resolution- A
3D image- A
Magnify up to 2mil times- A
Very expensive- D
What is the equation for magnification?
Mag= size of image/ size of real object
Function of the sperm
To fertilise the egg
Function of the red blood cell
To transport oxygen around the body through the blood
Function of the palisade cell
To help with photosynthesis
Function of the root hair cell
To absorb water and minerals for the plant
Function of the epithelia cell
To free trapped mucus and particles
Function of the fat cell
To break down fat
Function of the xylem
To carry water from the roots to the leaves
Function of the phloem
To transport food from the leaves to the rest of the plant
How is the red blood cell adapted?
Has no nucleus
Large surface area
Contains haemoglobin to pick up oxygen
How is the palisade cell adapted?
Large surface area
Lots of chloroplasts
How is the root hair cell adapted?
Large surface area
Thin cell wall
How is the epithelia cell adapted?
Has tails and cilia
Large surface area
How is the fat cell adapted?
Big fat store
How does bacteria multiply?
Binary fission
What type of reproduction occurs with bacteria?
Asexual
What is a nucleus?
Contains genetic information
What are genes?
Short sections of DNA that code for one protein or characteristic
What are gametes?
Sex cells
What are chromosomes?
Large molecules of DNA, which have a double helix structure
How many chromosomes does a sex cell have?
23
Order chromosome, nucleus, gene and cell starting with the smallest
Gene
Chromosome
Nucleus
Cell
What is a stem cell?
A cell that can become any other cell
Where are stem cells found?
Bone marrow and embryos
What can stem cells be used for?
Nerve cells
Heart muscles
Growing new plants
Test new drugs
What is differentiation?
As organisms develop cells become specialised for a particular function
Reasons for using embryo stem cells
Cure lots of people and deadly diseases
Adult stem cells may be rejected
Reasons against using embryo stem cells
Killing a human
Transfer diseases
Religion
Describe therapeutic cloning
You take a donor’s egg cell and a patient’s body cell
Remove both nucleus’ and fuse the patients into the donors
The cell the divides and becomes an embryo
Stem cells are grown
The cell specialises and is given to the patient
What is a diploid?
Pairs of chromosomes
What is a haploid?
Half number of chromosomes
Why do cells need to divide?
To regrow
Replace worn out cells
Repair damaged tissue
What is it called when cells divide?
Mitosis
Describe mitosis
Parent cell duplicates it chromosomes They line up in the middle The spindle fibres pull them to the poles Cell membrane and cytoplasm pinches Forms tow identical daughter cells
What is diffusion?
The movement of particles from a high to a low concentration until equilibrium is met
Where does diffusion happen in?
Liquids and gases
What type of process is diffusion?
Passive so it requires no energy
What factors affect diffusion?
Temperature- Particles have ore energy
Surface area- how much space there is to diffuse
Concentration gradient- The difference between the concentrations
Where does diffusion happen in the body?
Lungs
Small intestine
State three feature of the alveoli that make it perfect for diffusion
Good blood supply
Large surface area
Only one cell thin
How does diffusion happen in the small intestine?
Glucose move out of the intestine into the blood
Waste remains
Villi is present to increase the surface area
State why gills are perfect for diffusion
Only a few cells thin
Blood capillaries
Lots of filaments covered in leathery lamella for large surface area
State why leaves are perfect for diffusion
Flat, thin and large surface area
Spongey mesophyll layer increase the area for gas to exchange
What is active transport?
The movement of substances from a more dilute to a more concentrated solution
What type of process is active transport?
It is produced during respiration so it requires energy
Where does active transport occur?
Small intestine- gut to the blood
Root hair cell- soil to the roots
What is osmosis?
The movement of water from a dilute to a more concentrated solution through a partially permeable membrane
What is hypotonic?
When the concentration surrounding the cell is lower
What is hypertonic?
When the concentration surrounding the cell is higher
What is isotonic?
When the concentrations are the same
What is turgid?
When water enters the cell causing it to swell
What is plasmolysis?
When water leaves the cell making it shrivel up
