biochemistry p2 Flashcards
Function of cell wall
A rigid but flexible structure made of cellulose. It acts as a pressure vessel, preventing over-expansion when water enters the cell. It is found in mainly plant cells, but can also be in fungi, algae and some bacteria
Function of cell membrane
The entire cell is covered by thus and it is mostly composed of phospholipids. It is ‘selectively permeable’ and controls the entry and exit of various chemical into and out of the cell.
Function of flagella
Tail-like projection that helps cells move
Cillia
slender protuberances that project from the cell body. (eukaryotic cells only) they can also aid in motion or serve as sensory organelles or clear debris like in the lungs.
Mitochondria
Provides energy by producing ATP through cellular respiration
Chloroplast
Captures light energy and so is involved in photosynthesis, making glucose (is only found in plant cells since animals injest glucose)
Cytoplasm
where most cellular activities occur, like glycolysis and cell division. It also is the space that contains the organelles.
Lysosomes
An organelle that breaks down ‘worn out’ organelles, viruses/bacteria and food particles. It does this with digestive enzymes in an acidic environment
Ribosomes
They make proteins out of amino acids
Centrioles
A structure essential for cell division and the organisation of the spindle fibres in mitosis. Found only in animal cells
Rough endoplasmic reticulum
Where many ribosomes are attached, thus it helps synthesize proteins
Smooth endoplasmic reticulum
A series of canals that carry materials throughout the cell and help synthesize lipids such as steroids
Vacuole
A membrane-surrounded, fluid-filled “storage space containing water, sugar, minerals or enzymes. Function will vary depending on cell type
Golgi bodies/apparatus
a structure that stores and packages proteins (such as enzymes) and lipids
Nucleus
The small control center of the cell that contains DNA. It also has small ‘pores’ on it that allows materials to enter and exit
Nucleolus
A spherical structure of the nucleus that makes ribosomal RNA (rRNA)
Chromosomes
Thread-like structures that contain genetic info
Intro to membrane transport
- the cell membrane is semi-permeable: some substances can move across the cell membrane while others can’t
Concentration gradient
a difference in concentration between one side of the membrane and the other
Passive transport
Processes that allow substances to move across the membrane without energy. They use the concentration gradient.
ex. difusion, osmosis and facilitated difiusion
Active transport
movement of molecules against a concentration gradient
- requires energy in ATP
- includes active transport (endocytosis and exocytosis)
Facilitated diffusion
Large, polar or charged molecules like glucose need to use this because theyre to big to fit between phosphate heads. They use protein channels which are suited to each molecule to get through.
Simple difusion
Small non-polar molecules like o2 that can slip between phisphate heads and go through large non-polar portion of the membrane.
- Rate of diffusion is affected by: Molecules size, polarity, charge (charged ions cannot diffuse), temperature and pressure (hot–> faster)
Transport proteins
Movement of particles from relatively low to high concentration using a protein carrier