1. Key Concepts: Cells Flashcards
What are Cells?
The Building blocks of every organism on the planet
What are the types of Organism?
Eukaryotes and Prokaryotes
Characteristics of Eukaryotic cells?
Complex and include all Animal and Plant cells. Eukaryotes made up of eukaryotic organisms
Characteristics of Prokaryotic cells?
Smaller and simpler e.g. bacteria - single called organism. Prokaryote is a prokaryotic cell
What are the different parts of a cell called?
Subcellular structures
What are subcelluar structures of an ANIMAL cell?
- Nucleus - genetic material arranged in chromosomes -controls activity of cell
- Cytoplasm - gel where chemical reactions happen - contains enzymes that control reactions
- Cell Membranes - hold cell together - controls what goes in / out
- Mitochondria - where reactions for respiration take place. Respiration transfers energy that cell needs to work
- Ribosomes - translation of genetic material in synthesis of proteins
What are the subcellular structures of PLANT cells?
- Usually have all bits that animal cells have plus a few extra
- Rigid wall cell - made of cellulose. Support and strengthens cell
- Large Vacuole - contains cell sap - solution of sugar and salts that maintains internal pressure to support cell
- Chloroplasts - where photosynthesis occurs - make food for plant. Contains green chlorophyll
Characteristics of BACTERIA cells?
- Have no nucleus
- Smaller than Animal and Plant cells
- Chromosomal DNA - controls cell activity and replication - floats in cytoplasm (not nucleus)
- Ribosomes
- Cell membrane
- Plasmid DNA - small loops of extra DNA not part of chromosome. Contain genes e.g. for drug resistance that can be passed between bacteria
- Flagellum (Flagella) - long hair like that rotates to make bacterium move. Can move bacteria away from harmful toxins and towards nutrients or oxygen
What is DNA?
One long circular chromosome
What are SPECIALISED cells?
Have structure which makes them ADAPTED to their function e.g. EGG and SPERM cells
What happens in sexual reproduction?
- Nucleus of egg cell fuses with nucleus of sperm cell to create a fertilised egg
- Develops into an embryo
- Nucleus of egg and sperm cells contain half number of chromosomes in a normal body cell - called HAPLOID
- When they combine at FERTILISATION resulting cell will have the right number of chromosomes
What are characteristics of an EGG cell?
- Carries the female DNA
- Nourishes the embryo in early stages
- Nutrients in the cytoplasm to feed embryo
- Haploid nucleus
- After fertilisation membrane changes structure to stop more sperm getting in. Ensuring offspring have right amount of DNA
What are characteristics of a SPERM cell?
- Transports male DNA to the female’s egg
- Flagella so can swim to egg
- Lots of mitochondria in middle to provide energy (from respiration) needed to swim the distance
- Has an across acrosome at front head - stores enzymes to digest way through egg membrane
- Contains HAPLOID nucleus
What are characteristics of CILIATED EPITHELIAL cell?
- Specialised for moving materials
- Epithelial cells line the surface of organs
- Some have CILLA (hair like) on top surface
- Function of ciliated epithelial cells is to move substances. Cilla beat to move substance in one direction along surface
- E.G. lining of airways - Help move mucus (and trapped air particles) up the throat so can be swallowed and doesn’t reach lungs
