3.1 In The Beginning Flashcards
(29 cards)
What are the two basic types of cell?
Eukaryotic and Prokaryotic
What is the function of the cell membrane?
To control what enters and exits the cell
What is the function of ribosomes?
Move along mRNA molecules and read the nucleotide code to produce proteins
What are ribosomes made of?
rRNA
What is the function of mitochondria?
To produce energy in the form of ATP during respiration
What are the three main features of a mitochondria?
Outer membrane, matrix and cristae which give a larger surface area
What is the function of the rough endoplasmic reticulum?
(rER)
has ribosomes and is involved with protein synthesis as a transport system
What is the function of the smooth endoplasmic reticulum?
(sER)
involved with the synthesis and transport of lipids
What is the function of the golgi apparatus?
Made up of flattened membrane bound sacs
package proteins
transport and store lipids
form lysosomes
What is the function of lysosomes?
contain digestive enzymes to remove worn out organelles
What is the function of the 2 centrioles?
Produce the spindles to pull chromosomes apart during cell division
What are the features and functions of the nucleus
Contains DNA
Nuclear membrane- double membrane containing pores
Chromatin- long entangled chromosomes taht condense during cell division
Nucleolus- makes rRNA and assembles proteins
What is the function of the cytoplasm?
contains all the organelles within the cell
Which 3 organelles do prokaryotes not have that eukaryotes do?
nuclear envelope
mitochondria
centriole
What is the function of the capsule?
Protection and to prevent dehydration
What is the function of the mesosome?
site of respiration
Describe the process of protein packaging.
- Transcription of DNA to mRNA
- mRNA leaves the nucleus
- Protein made on ribosome brought to rER
- Proteins move through rER assuming 3D shape
- Vesicles containing proteins pinched off rER
- Vesicles fuse to form cisternae of golgi apparatus
- Proteins modified by enzymes and are sorted as the parts temporarily fuse
- Vesicles containing proteins pinched off trans face and targeted to specific areas
- Vesicles fuse with cell membrane to release contents
Describe fertilisation in humans.
- sperm reaches ovum
- chemicals from surrounding cells trigger acrosome reaction so sperm fuses to surface membrane
- digestive enzymes in acrosome are released
- enzymes digest follicle layer and zona pellucida
- sperm nucleus enters ovum
- Ovum lysosomes release enzymes that thicken zona pellucida to prevent other sperm entering
- Nuclei of ovum and sperm fuse to form a diploid nucleus
Describe fertilisation in plants.
- Pollen grain lands on the stigma
- genetically compatible grains produce enzymes that digest the style
- Pollen grain contains two nuclei; tube nuclues that generates pollen tube and generative nucleus that splits in two so it is haploid
- Pollen tube grows into embryo sac
- One of the male nuclei fuses with egg nuclei to form diploid nucleus
- Other nucleus fuses with polar nuclei to form endosperm (3n) which is a food store
What are the two distinct parts of the cell cycle?
Interphase and Division
What happens during interphase?
Cell prepares for division
G1- new cell components e.g. organelles made
S-New DNA synthesised
G2- Enzymes are generated
In which interphase stage is the length variable?
G1
What happens to the chromosomes during interphase?
Individual chromosomes unravel so genes can be transcribed to make new proteins.
Copies of the DNA are made for the new cells to produce sister chromatids
What are the 4 stages of mitosis?
Prophase Metaphase Anapahase Telophase Cytokinesis
