From Big To Small Flashcards
What is the nucleus and what does it do
It controls all the activity in the cell and contains the chromosomes (strands of DNA which carry the genes)
What does the cell membrane do
The boundary between the cytoplasm and the cell’s surroundings - it controls what substances go in and out of the cell (selectively permeable)
What is the purpose of the cell wall
To maintain the structure of a plant cell. Made of cellulose
What do mitochondria do
Carries out some reactions of aerobic respiration and produces ATP
What do chloroplasts do
absorb light energy and use it to carry out the chemical reactions of photosynthesis
what is the cell membrane
boundary between the cytoplasm and the cell’s surroundings
Cytoplasm
Jelly-like liquid where chemical reactions occur
what do Ribosomes do?
Synthesise proteins from amino acids
Vacuole
Filled with watery liquid called cell sap. stores dissolved sugars, mineral ions and other substances
Starch and glycogen are made up of
Simple sugars
Lipids are made up of
Fatty acids and glycerol
ATP provides
energy for cells
anaerobic respiration equation
glucose -> lactic acid
Balanced symbol equation for aerobic respiration
C6 H12 O6 + 6O2 -> 6CO2 + 6H2O
What is ATP and why is it needed
Glucose is like a truckload of energy so every one glucose molecule(that is hard to break down) is broken down into 33 ATP molecules that are easy to break down
Common Features of a plant cell
Chloroplasts
Cellulose cell wall
Four eukaryotic kingdoms
Plant, Animal, Funghi, Protoctista
Common features of protoctista
All single celled
Cells contain: chloroplasts, cell wall, flagella
What is a eukaryote
Organism that contains a proper nucleus
How do protoctista get their nutrients
Some photosynthesise while others feed on other organisms or organic remains
How do animals and funghi store carbohydrates
as glycogen
How do plants store their carbohydrates
as starch or sucrose
Common features of funghi cells
No chloroplasts
Chitin cell wall
Many nuclei per cell
How do funghi get nutrients
Feed by saprotrophic nutrition
What is a prokaryote
an organism that has no proper nucleus
name one prokaryote
bacteria
What is a pathogen
microorganisms which cause infectious disease
Structure of a virus
A strand of genetic material surrounded by a protein coat
Bacterial cells contains
plasmids
capsule
flagella
single chromosome
Saprotrophic nutrition
when organisms secrete digestive enzymes outside of their cells onto the dead organisms. The dead organism is broken down into small, soluble molecules which are then absorbed by the decomposer
What is cell respiration
the process of breaking down food molecules to release ATP
All cells need a source of energy to be able to carry out life processes. this is called
ATP
How is ATP produced
During aerobic respiration, oxygen is used to break down glucose and release energy. some of this energy is released as heat but most is trapped in a usable form of ATP
Why can unicellular organisms rely on diffusion
They have a large surface area to volume ratio
Diffusion
The movement of particles from an area with high concentration to low concentration
What is a stem cell
A single cell that can replicate itself or differentiate into many cell types. All cells begin as stem cells
Adaptations of a red blood cell
- contains haemoglobin
- no nucleus
- Biconcave shaped
Adaptations of a sperm cell
- Flagellum
- many mitochondria
- Acrosome (package of enzymes to digest the jelly layer surrounding the egg cell
Adaptations of a palisade cell (leaf)
- packed with chloroplasts
- tall and thin (cells can pack tightly together so more of the light reaching the leaf can be absorbed
What elements are Carbohydrates made up of
Carbon, Hydrogen, and Oxygen
Many sugar molecules (1000s) are joined together to make which two carbohydrates
Starch and Glycogen
What is starch used for
to store glucose in plants
What is glycogen used for
To store glucose in animals and funghi
What two things are the smallest units of carbohydrates
The simple sugars: glucose and fructose
What do glucose and fructose make up when joined
sucrose
What elements are fats made up of
Carbon, Hydrogen and Oxygen
What ‘chains’ are lipids made out of
3 fatty acid chains joined to a glycerol molecule
What are lipids used for in the body
- energy storage
- thermal insulation
- electrical insulation (around nerve cells)
- buoyancy
- part of cell membranes
What elements are proteins made up of
carbon, hydrogen, oxygen and nitrogen
What ‘chains’ are proteins made out of
amino acids
Functions of proteins in the body
- structural molecules (eg collagen and keratin)
- Controlling chemical reactions (enzymes)
- messenger molecules (hormones)
- combating disease (antibodies)
- transport (haemoglobin)
what is an enzyme
A catalyst - a chemical which increases the rate of reaction without being used up itself in the reaction
How do enzymes work
- substrate and enzyme collide and bind together
- Binding to the site strains the chemical bonds in the substrate so the reaction occurs by an alternate pathway with a lower activation energy
- once this has occurred the products don’t fit the active site as well so they are released
What affects the rate of an enzyme controlled reaction
Temperature (more kinetic energy so more successful collisions)
pH (denatured)
Concentration of substrate or enzyme
What is a chromosome
a linear strand of DNA
What is a genome
the total DNA of an organism - coding for all its charateristics
what is a gene
a short section of DNA within a chromosome
What is DNA
the chemical which contains the information for making proteins - it contains the instructions for all the structures and reactions needed in the cell of an organism
What is the structure of DNA
a double stranded molecule made of two chains of nucleotides. these strands coil to form a double helix
What are the four bases of a nucleotide and what are their pairs
- adenine ALWAYS PAIRS WITH
- thymine
- cytosine ALWAYS PAIRS WITH
- guanine
What three thing is a nucleotide made out of
- a sugar (deoxyribose)
- a phosphate
- a nitrogenous base
what are eukaryotes
organisms whose cells contain a nucleus
Differences between funghi and protoctista
fungi = mostly multi-cellular
protoctista = all single celled
f = cells have no chloroplasts and a chitin cell wall
p = have chloroplasts but normal cell wall
f = feed by saprotrophic nutrition
p = photosynthesis or feeding on other organisms
Features of bacteria
- prokaryotic
- single cellular
- very small
- cell wall, plasmids
- no nucleus (genetic material in the form of a single (wiggly) circular chromosome
what is a pathogen
microorganism which cause infectious disease. they harm the host by releasing toxins or damaging cells
What is the structure of viruses
a simple strand of genetic material surrounded by a protein coat
how to viruses reproduce
- enter a host cell
- take over the ribosomes and enzymes in the cell to make new virus particles
- when many new viruses have been made the cell dies and the new viruses are released
how does saprotrophic nutrition occur
- secrete digestive enzymes outside of their cells onto dead organisms
- the dead organism is broken down into small soluble molecules
- absorbed by organism
What kingdoms store carbohydrates as glycogen
Animals
Fungi
